Question

How many terms of the ap, -6, -11/2 , -5....Are needed to give the sum -25? Explain the right answer?

Answer 1

$- 6 - 11 \div 2 - 5 = - 25 \\ - 6 - 5.5 - 5 = 25 \\ - 16.5 \: is \: \: not \: equal \: to \: - 25$