Question

In an arithmetic sequence 30 is the first term and 300 is the sum of first 8 terms. Write the sequence.

​

Answer 1

The first term a is given by 30, let the

:

common difference be d

Sum of first three terms =300

Sum of n terms of an AP is given by (n=2)x(2a+(n-1)xd)

In this case n=3 and a=30

(3÷2)x(60+2d)=300

60+2d=200

2d=140

d=70

The second term is 30+70=100

the third term is 100+70 = 170