Question

find the sum of first ten multiples of 4

Answer 1

Answer:

First 10 multiples of 4 are:–

4, 8, 12, 16, 20, 24, 28, 32, 36, 40

So, a = 4

l {Last term} = 40

d = 4

n = 10

So,

S10 =

\frac{n}{2 \times (a + l)}

2×(a+l)

n

= \frac{10}{2 \times (4 + 40)}=

2×(4+40)

10

= 5 \times 44=5×44

= 220=220