Explanation

If 8 men eat 16 mangoes in 15 minutes, it means each man eats 16/8 = 2 mangoes in 15 minutes.

So, in 30 minutes, each man will eat 2×2 = 4 mangoes.

Therefore, if there are 16 men eating for 30 minutes, they will eat 16×4 = 64 mangoes.