#### Question

Find the sum of the following APs:

2, 7, 12, . . ., to 10 terms.

#### Solution

2, 7, 12 ,…, to 10 terms

For this A.P.,

a = 2

d = a_{2} − a_{1} = 7 − 2 = 5

n = 10

We know that,

S_{n} = `n/2 [2a + (n - 1) d]`

S_{10} = `10/2 [2(2) + (10 - 1) × 5]`

= 5[4 + (9) × (5)]

= 5 × 49 = 245

Is there an error in this question or solution?

Solution Find the sum of the following APs: 2, 7, 12, . . ., to 10 terms. Concept: Sum of First n Terms of an AP.