Question

the last term of the series in A.P is 31 and the sum is 136 and common difference is 4. Find the value of first term and the number of term in the series

Answer 1

hope this helps! cheers :)

Answer 2

Sum: 136,d:4,l:31 a:? and n:?

To get a u can Subtract last term by 4(d)

U get:3,7,11,15,19,23,27,31(a:3)

Now you can use formula

S=n/2(a+l)

136=n/2(3+31)

136×2=3n+31n

272=34n

n=272/34

n=8

This is the easiest way to solve...hope it wil help.