Question

The number of common prime factors of 75,60,105 is - (A) 2 (B) 3 (C) 4 (D) 5

Answer 1

hi friend your answer is B 3
first write their factors then choose the prime ones and the answer would be 3

Answer 2

Prime factor of 75=3×5×5
Prime factor of 60=2×2×3×5
Prime factor of 105=3×5×7

So common prime factors=3×5

So no. of common factors=2

I should suggest you to go with option (A)