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MathsMediumNumerical2022 · 26 Jun Shift 1

Q86.Let A = {n ∈ N : H. C. F. (n, 45) = 1} and let B = {2k : k ∈{1, 2, … , 100}} . Then the sum of all the elements of A ∩B is _____.

What This Question Tests

This problem requires identifying elements in a set based on HCF conditions, then summing specific elements from an arithmetic progression using the principle of inclusion-exclusion related to divisibility.

Concepts Tested

HCF (Greatest Common Divisor)Principle of Inclusion-Exclusion (for counting/summing multiples)Arithmetic progression sumSet intersection

Formulas Used

Sum of AP = (n/2)(a + l)

Number of terms not divisible by p and q = Total - (divisible by p) - (divisible by q) + (divisible by pq)

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