The sum of A.P. 4, 7, 10, 13, …….. upto 20 terms is :

1. 650

2. 10 × 27

3. 510

4. 1300

In A.P. 4, 7, 10, 13, …….. upto 20 terms

First term (a) = 4

Common difference (d) = 7 - 4 = 3

By formula,

Sum of n terms = $\dfrac{n}{2}[2a + (n - 1)d]$

Sum of above A.P. (upto 20 terms)

$= \dfrac{20}{2}[2 \times 4 + (20 - 1) \times 3] \\[1em] = 10 \times [8 + 19 \times 3] \\[1em] = 10 \times [8 + 57] \\[1em] = 10 \times 65 \\[1em] = 650.$

Hence, Option 1 is the correct option.