MEDIUM
JEE Main/Advance
IMPORTANT
Earn 100

A quadratic equation is chosen from the set of all quadratic equations which are unchanged by squaring their roots. The chance that the chosen equation has equal roots is -

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Important Questions on Probability

HARD
JEE Main/Advance
IMPORTANT
5 persons entered the lift cabin on the ground floor of an 8 floor building. Suppose that each of them independently and with equal probability, can leave the cabin at any other floor, starting from the first. The probability that all 5 persons leave at different floors is -
HARD
JEE Main/Advance
IMPORTANT
If the integers m and n are chosen at random between 1 and 100, then the probability that a number of the form 7m+7n is divisible by 5, equals
EASY
JEE Main/Advance
IMPORTANT
There are 10 Prizes, five A's, three B's, and two C's, placed in identical sealed envelopes for the top 10 Contestants in a mathematics contest. The prizes are awarded by allowing winner to select an envelope at random from those remaining. When the 8th Contestant goes to select the prize, the probability that the remaining three prizes are one A, one B and one C is,
MEDIUM
JEE Main/Advance
IMPORTANT
A & B are two independent events such that PA¯=0.7, PB¯=a & PA∪B=0.8, then a=
HARD
JEE Main/Advance
IMPORTANT
A determinant is chosen at random from the set of all determinant of order 2 with elements 0 or 1 only. The probability that the determinant chosen has the value non negative is -
HARD
JEE Main/Advance
IMPORTANT
If two of the 64 squares are chosen at random on a chess board, the probability that they have a side in common is -
HARD
JEE Main/Advance
IMPORTANT
Let 0<PA<1, 0<PB<1 and PA∪B=PA+PB-PAPB. Then -
HARD
JEE Main/Advance
IMPORTANT
15 coupons are numbered 1,2,3,………,15 respectively. 7 coupons are selected at random one at a time with replacement. The probability that the largest number appearing on a selected coupon is 9 is -