Question

the first term of an A.P is 5 and the common difference is 10.complete the following activity to find the sum of first 10 terms of the A.P​

Answer 1

Answer:

a=5

d=10

n=10

sn=?

so,

using formula sn = n÷2(2a +(n-1)×d

sn= 10÷2(2×5 + (10-1)×10

= 5 (10 + (9×10)

= 5(10+90)

= 5×100

=500