Q60 / 90 · JEE Main 2022 (26 Jun Shift 2) · Mathematics

The total number of 3-digit numbers, whose greatest common divisor with 36 is 2, is ______.

Correct answer: 150

Solution

Prime factorisation of 36=2×2×3×3

So, for number having G.C.D with 36 to be 2, the number should be odd multiple of 2 and does not have factor 3 and 9

⇒Odd multiple of 2 are

102,106,110,114…….998  225 numbers

⇒No. of multiples of 3 are

102,114,126…….990 75 numbers

Which also include multiple of 9

Hence, Required =225-75=150

Hence, the correct answer is 150.

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