How Many Terms Make 78?

Arithmetic ProgressionsVideo challenge · SAV38

How Many Terms Make 78?

CBSE Class 10 · Solve it one decision at a time. A wrong pick earns a nudge, never the answer.

Step 1 of 7

The problem

How many terms of the AP 24,21,18,…24, 21, 18, \ldots must be taken so that their sum is 7878? Give every possible value of nn.

Step 1 · Your move

Before the guided steps, which value or values of nn did you get?

24,  24,\;21,  21,\;18,  18,\;…Sn=78\ldots \qquad S_n = 78
Helpful?