Question

Find the sum of the first
40 positive integer divisible by 6

Answer 1

Its is done by A.P . I think it will help you .

Answer 2

Sum is 4920

Explanation :

★ Given :-

A.P :- 6, 12, 18, 24 ........ 240

• First term (a) = 6
• Common Difference (d) = 6
• Last term (L) = 240
• Number of terms (n) = 40

________________________

★ To Find :-

We have to find the Sum of first 40 term of the A.P

________________________

★ Solution :-

As, we have to find the Sum of first 40 terms of the A.P then Number of terms (n) will bw 40.

A.T.Q

$S_{n} = \frac{n}{2} 2a + (n - 1)d \\ \\ S_{n} = \frac{40}{2}2(6) + (40 - 1)6 \\ \\ S_{n} = 20(12 + 39 \times 6) \\ \\ S_{n} = 20(12 + 234) \\ \\ S_{n} = 20(246) \\ \\ S_{n} = 4920$

Therefore, Sum of 40 terms of the A.P is 4920.