The first term of an A.P. is 5 and the last term is 45. If the sum of all the terms is 400, the number of terms is... | MCQ 1m | Maths | SuperPadhai

Arithmetic Progressions > Question

MCQ1 markYear: 2020EasyCBSE Class 10

arithmetic-progressionssumnumber-of-terms

Question

The first term of an A.P. is 5 and the last term is 45. If the sum of all the terms is 400, the number of terms is

Solution

1

S_{n} = \frac{n}{2} (a + l) \Rightarrow 400 = \frac{n}{2} (5 + 45) \Rightarrow n = 16

+1 mark

Practice this question interactively with step-by-step AI feedback

Sign up for SuperPadhai