Question

2. Lee earned $240 in the first week, S350 in the second week and $460 in the third week, and so on in an arithmetic

sequence. How much did he earn in the first 5 weeks?

Answer 1

$2,300.

Explanation:

Sum of n terms of an A. S. is

Sn = (n/2)[2a + (n-1)d] where a = the first term and d = the common difference.

Here the common difference = 110 and the first term = 240 so:

Sum of 5 terms

= (5/2[2*240 + (5 - 1)*110)

= $2,300.