PYQSidePowered by
ExamsMy practice
A board has 16 squares as shown in the figure : [figure] Out of these 16 squares, two squares are chosen at random. The probability that they have no side in common is :
(2) 45
Total pairs: 16C2=120. Pairs with a common side = neighbouring squares (links shown):
[figure]
horizontal 4 3=12, vertical 4 3=12, so 24 pairs.
P=1- 24120= 45
Answer: (2)
A bag contains 6 blue and 6 green balls. Pairs of balls are drawn without replacement until the bag is empty. The probability that each drawn pair consists of one blue and one green ball is :
A coin is tossed 8 times. If the probability that exactly 4 heads appear in the first six tosses and exactly 3 heads appear in the last five tosses is p, then 96p is equal to .
From a month of 31 days, 3 different dates are selected at random. If the probability that these dates are in an increasing A.P. is equal to ab, where a, b N and (a, b)=1, then a+b is equal to .
Let a, b, c \1, 2, 3, 4\. If the probability, that ax2+2 2 bx+c>0 for all x R, is mn, (m, n)=1, then m+n is equal to .
A man throws a fair coin repeatedly. He gets 10 points for each head he throws and 5 points for each tail he throws. If the probability that he gets exactly 30 points is mn, (m, n)=1, then m+n is equal to :
Let S be a set of 5 elements and P(S) denote the power set of S. Let E be an event of choosing an ordered pair (A, B) from the set P(S) P(S) such that A B = . If the probability of the event E is 3p2q, where p, q N, then p + q is equal to .
From the first 100 natural numbers, two numbers first a and then b are selected randomly without replacement. If the probability that a - b 10 is mn, (m, n) = 1, then m + n is equal to .
Two distinct numbers a and b are selected at random from 1, 2, 3, , 50. The probability, that their product ab is divisible by 3, is
The probability of forming a 12 persons committee from 4 engineers, 2 doctors and 10 professors containing at least 3 engineers and at least 1 doctor, is
Three distinct numbers are selected randomly from the set \1, 2, 3, , 40\. If the probability, that the selected numbers are in an increasing G.P., is mn, (m, n) = 1, then m + n is equal to .