HARD
JEE Main
IMPORTANT
Earn 100

Let i=150Xi=i=1nYi=T, where each Xi contains 10 elements and each Yi contains 5 elements. If each element of the set T is an element of exactly 20 of sets Xi's and exactly 6 of sets Yi's then n is equal to :

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Important Questions on Set Theory and Relations

EASY
JEE Main
IMPORTANT
A survey shows that 73% of the persons working in an office like coffee, whereas 65% like tea. If x denotes the percentage of them, who like both coffee and tea, then x cannot be:
MEDIUM
JEE Main
IMPORTANT
Set A has m elements and set B has n elements. If the total number of subsets of A is 112 more than the total number of subsets of B, then the value of m·n is___.
EASY
JEE Main
IMPORTANT
Let X=nN:1n50. If A=nX: n is a multiple of 2 and B=nX: n is a multiple of 7, then the number of elements in the smallest subset of X, containing both A and B, is.
MEDIUM
JEE Main
IMPORTANT
Two newspapers A and B are published in a city. It is known that 25% of the city population reads A and 20% reads B while 8% reads both A and B. Further, 30% of those who read A but not B look into advertisements and 40% of those who read B but not A also look into advertisements, while 50% of those who read both A and B look into advertisements. Then the percentage of the population who look into advertisements is:
MEDIUM
JEE Main
IMPORTANT
In a class of 140 students numbered 1 to140 , all even numbered students opted Mathematics course, those whose number is divisible by 3 opted Physics course and those whose number is divisible by 5 opted Chemistry course. Then the number of students who did not opt for any of the three courses is:
HARD
JEE Main
IMPORTANT
Let A, B and C  be sets such that ϕABC. Then which of the following statements is not true?
EASY
JEE Main
IMPORTANT
Let S=1, 2, 3, .,100, then number of non-empty subsets A of S such that the product of elements in A is even is :