JEE Previous Year Question

The sum of all the elements of the set { {1, 2,..., 100} : HCF (, 24) = 1} is_____.

Topic: JEE PYQ

Answer: 1633. Full step-by-step solution below.

Correct answer: 1633

Solution

(1633)
HCF (, 24) = 1
Now, 24 = 22.3
is not the multiple of 2 or 3
Sum of values of
= S(U) -{S(multiple of 2) + S (multiple of 3) - S(multiple of 6)}
= (1 + 2 + 3 +......100) - (2 + 4 + 6.....+ 100) - (3 + 6 +.....99)+ (6+12+.....+96)

= 5050 - 2550 - 1683 + 816 = 1633 Ans.

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