Q12 of 102 Page 410

Find the sum of n term of an AP whose r^th term is (5r + 1).

To Find: The sum of n terms of an AP

Given: The r^th term.

The r^th term of the series is given by

Sum of the series is given by sum upto n terms of t_r

Find the value of x such that 25 + 22 + 19 + 16 + …. + x = 112.

Find the r^th term of the AP, the sum of whose first n terms is (3n² + 2n).

If the sum of a certain number of terms of the AP 27, 24, 21, 18, …. is –30, find the last term.

How many terms of the AP 26, 21 16, 11, …. are needed to give the sum 11?

Find the sum of n term of an AP whose rth term is (5r + 1).