Question

Eighteen integers are multiplied together. What will be the sign of their product, if:

(i) 15 of them are negative and 3 are positive?

Answer 1

The product of an odd number of negative integers is always negative.

The product of an even number of negative integers is always positive.

Here we have 18 integers that are multiplied together.

Out of 18, 15 are negative and 3 are positive.

Since the number of negative integers is odd (15) their product would always be a negative integer.

$\therefore$ By multiplying 15 negative and 3 positive integers, the sign of their product will be negative.