Friday, 27 August 2021
Wednesday, 25 August 2021
real number cbse previous question
Real Number class 10 short notes
Monday, 23 August 2021
problems on probability
OBJECTIVE
1. If there coins are tossed simultaneously, then the probability of getting at least two heads, is
(A) 1/4 (B) 3/8 (C) 1/2 (D) 1/4
2. A bag contains three green marbles four blue marbles, and two orange marbles. If marble is picked at random, then the probability that it is not a orange marble is
(A) 1/4 (B) 1/3 (C) 4/9 (D) 7/9
3. A number is selected from number 1 to 27. The probability that it is prime is
(A) 2/3 (B) 1/6 (C) 1/3 (D) 2/9
4. IF (P(E) = 0.05, then P (not E) =
(A) -0.05 (B) 0.5 (C) 0.9 (D) 0.95
5. A bulb is taken out at random from a box of 600 electric bulbs that contains 12 defective bulbs. Then the probability of a non-defective bulb is
(A) 0.02 (B) 0.98 (C) 0.50 (D) None
SUBJECTIVE
1. To dice are thrown simultaneously. Find the probability of getting :
(i) An even number of the sum
(ii) The sum as a prime number
(iii) A total of at least 10
(iv) A multiple of 2 on one dice and a multiple of 3 on the other.
2. Find the probability that a leap year selected at random will contain 53 Tuesdays.
3. A bag contains 12 balls out of which x are white.(i) If one ball is drawn at random, what is the probability it will be a white ball ? (ii) If 6 more white balls are put in the box. The probability of drawing a white ball will be double than that is (i). Find x.
4. In a class, there are 18 girls and 16 boys. The class teacher wants to choose one pupil for class monitor. What she does, she writes the name of each pupil a card and puts them into a basket and mixes thoroughly. A child is asked to pick one card from the basket. What is the probability that the name written on the card is: (i) The name of a girl (ii) The name of boy ?
5. The probability of selecting a green marble at random from a jar that contains only green, white and yellow marbles is 1/4. The probability of selecting a white marble from the same jar is 1/3. If this jar contains 10 yellow marbles. What is the total number of marbles in the jar ?
6. A card is drawn at random from a well suffled desk of playing cards. Find the probability that the card drawn is (i) A card of spade or an ace (ii) A red king (iii) Neither a king nor a queen (iv) Either a king or a queen
7. There are 30 cards of same size in a bag on which number 1 to 30 are written. One card is taken out of the bag at random. Find the probability that the number of the selected card is not divisible by 3.
8. In figure points A,B,C and D are the centers of four circles that each have a radius of length on unit. If a point is selected at random from the interior of square ABCD. What is the probability that the point will be chosen from the shaded region ?
9. A bag contains 5 white balls, 6 red balls, 6 black balls and 8 green balls. One ball is drawn at random from the bag. Find the probability that the ball drawn is (i) White (ii) Red or black (iii) Note green (iv) Neither white nor black [CBSE - 2006]
10. A bag contains 4 red and 6 black balls. A ball is taken out of the bag at random. Find the probability of getting a black ball. [CBSE - 2008]
11. Cards. marked with number 5 to 50, are placed in a box and mixed thoroughly. A card is drawn from the box at random. Find the probability that the number on the taken out card is (i) a prime number less than 10. (ii) a number which is a perfect square.
#jee #math #probability
Thursday, 19 August 2021
Probability
P(A) = (Total number of favourable outcomes)/(Total number of possible outcomes)
= m/n
And 0 £ P(A) £ 1
If, P(A) = 0, then A
is called impossible event
If, P(A) = 1, then A is called sure event
P(A) + P (A") = 1
Where P(A) = probability of occurrence of A.
P (A') = probability of non - occurrence of A.
Ex.1 A box contains 5 red balls, 4 green balls and 7
white balls. A ball is drawn at random from the box. Find the probability that
the ball drawn is (i) white (ii) neither red nor white
Sol. Total number of balls in the bag = 5 + 4 + 7 =
16
\
Total number of elementary events =16
(i) There are 7 white balls in the bag.
\ Favorable number of elementary events = 7
P(Getting a white ball ) = (Total No. of elementaryevents) /(Total No. favourable elementaryevents)
= 7 /16
(ii) There are 4 balls that are neither red nor white
Favorable number of elementary events = 4
Hence, P (Getting neither red not white ball) = 4/16 =1/4
Ex.2 All the three face cards of spades are removed from a well-shuffled pack of 52 cards. A card is then drawn at random from the remaining pack. Find the probability of getting [CBSE - 2007] (i) black face card (ii) a queen (iii) a black card.
Sol. After removing three face cards of spades (king, queen, jack) from a deck of 52 playing cards, there are 49 cards left in the pack.
Out of these 49 cards one card can be chosen in 49 ways.
Therefore, Total number of elementary events = 49
(i) There are 6 black face cards out of which 3 face cards of spades are already removed.
So, out of remaining 3 black face cards one black face card ban be chosen in 3 ways.
Therefore, Favorable number of elementary events = 3
Hence, P (Getting a black face card ) = 3/49
(ii) There are 3 queens in the remaining 49 cards.
So, out of these three queens, on queen can be chosen in 3 ways
Therefore, Favorable number of elementary events = 3
Hence P (Getting a queen) = 3/49
(iii) There are 23 black cards in the remaining 49 cards,
So, out to these 23 black card, one black card can be chosen in 23 ways
Therefore, Favorable number of elementary events = 23
Hence, P (Getting a black card) = 23/49
Ex.3 A die is thrown, Find the probability of (i) prime number (ii) multiple of 2 or 3 (iii) a number greater than 3.
Sol.
In a single throw of die any one of six numbers 1,2,3,4,5,6 can be obtained.
Therefore, the tome number of elementary events associated with the random experiment of throwing a die is 6.
(i) Let A denote the event “Getting a prime no”.
Clearly, event A occurs if any one of 2,3,5 comes as out come.
Therefore, Favorable number of elementary events = 3
Hence, P (Getting a prime no.) = 3/6=1/2
(ii) An multiple of 2 or 3 is obtained if we obtain one of the numbers 2,3,4,6 as out comes.
Therefore, Favorable number of elementary events = 4
Hence, P (Getting multiple of 2 or 3) = 4/6=2/3
(iii) The event “Getting a number greater than 3” will occur, if we obtain one of number 4,5,6 as an out come.
Therefore, Favorable number of out comes = 3
Hence, required probability = 3/6=1/2
Ex.4 Two unbiased coins are tossed simultaneously. Find the probability of getting (i) two heads (ii) at least one head (iii) at most one head.
Sol.
If two unbiased coins are tossed simultaneously,
we obtain any one of the following as an out come : HH, HT, TH, TT
Therefore, Total number of elementary events = 4
(i) Two heads are obtained if elementary event HH occurs.
Therefore, Favorable number of events = 1 Hence, P (Two heads) = 1/4
(ii) At least one head is obtained if any one of the following elementary events happen : HH, HT, TH
Therefore, favorable number of events = 3
Hence P (At least one head) = 3/4
(iii) If one of the elementary events HT, TH, TT occurs, than at most one head is obtained
Therefore, favorable number of events = 3
Hence, P (At most one head) = 3/3
Ex.5 A box contains 20 balls bearing numbers, 1,2,3,4…...20. A ball is drawn at random from the box. What is the probability that the number of the ball is (i) an odd number (ii) divisible by 2 or 3 (iii) prime number
Sol. Here, total numbers are 20.
Total number of elementary events = 20
(i) The number selected will be odd number, if it is elected from 1,3,5,7,9,11,13,15,17,19
Therefore, Favorable number of elementary events = 10
Hence, P (An odd number ) = 10/20=1/2
(ii) Number divisible by 2 or 3 are 2,3,4,6,8,9,10,12,14,15,16,18,20
Therefore, Favorable number of elementary events = 13
P (Number divisible by 2 or 3) = 13/20
(iii) There are 8 prime number from 1 to 20 i.e., 2,3,5,7,11,13,17,19
Therefore, Favorable number of elementary events = 8
P (prime number ) = 8/20=2/5
Ex.6 A die is drop at random on the rectangular region as shown in figure. What is the probability that it will land inside the circle with diameter 1m ?
comment answer of this question
Sunday, 25 July 2021
Saturday, 24 July 2021
Class 10 new syllabus session 2021-2022
UNIT-ALGEBRA
Saturday, 3 July 2021
Pair of Linear Equations in Two Variables Linear Equation
Solution of an Equation
- Each solution (x, y) of a linear equation in two variables.
- ax + by + c = 0, corresponds to a point on the line representing the equation, and vice-versa
Pair of Linear Equations in Two Variables
- The solution is (4, 2), the point of intersection.
- To summarize the behavior of lines representing a pair of linear equations in two variables:
- The lines may intersect in a single point. In this case, the pair of equations has a unique solution(consistent pair of equations).
- The lines may be parallel. In this case, the equations have no solution (inconsistent pair of equations).
- The lines may be coincident. In this case, the equations have infinitely many solutions [dependent (consistent) pair of equations]
Substitution Method
- Find the value of one variable, say y in terms of the other variable, i.e., x from either equation,whichever is convenient.
- Substitute this value of y in the other equation, and reduce it to an equation in one variable,i.e., in terms of x, which can be solved. Sometimes, you can get statements with no variable. If this statement is true, you can conclude that the pair of linear equations has infinitely many solutions. If the statement is false, then the pair of linear equations is inconsistent.
- Substitute the value of x (or y) obtained in Step 2 in the equation used in Step 1 to obtain the value of the other variable.
Elimination Method
- First multiply both the equations by some suitable non-zero constants to make the coefficients of one variable (either x or y) numerically equal.
- Then add or subtract one equation from the other so that one variable gets eliminated. If you get an equation in one variable, go to Step 3. If in Step 2, we obtain a true statement involving no variable, then the original pair of equations has infinitely many solutions. If in Step 2, we obtain a false statement involving no variable, then the original pair of equations has no solution, i.e., it is inconsistent.
- Solve the equation in one variable (x or y) so obtained to get its value.
- Substitute this value of x (or y) in either of the original equations to get the value of the other
Cross Multiplication Method
Thursday, 1 July 2021
Linear equation in two variables Previous year question paper class 10.
6x- 5y= 9
3x – 2y + 7 = 0
Sunday, 9 May 2021
Real numbers NCERT CHAPTER 1 previous question paper class 10 MATHEMATICS
Wednesday, 7 April 2021
Monday, 5 April 2021
Polynomial Previous year question paper class 10. NCERT CHAPTER 2
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