Suppose that you plan on taking a summer job selling magazines subscriptions . the magazine company will you pay $0.75 for selling the first subscription .for each additional subscriptions sold, the magazine company will pay you $0.20 more than what was paid for the previous subscription .how much money will you earn by selling 175 magazine subscriptions ?

Money earned by selling 175 magazine subscriptions will be 3176.25

Solution:

Given that you are planning to take a summer job selling magazine subscription.

For first subscription, magazine company will help you to pay $0.75

For each additional subscription sold, magazine company will pay you $0.20 more than what was paid for previous subscription.

So for second subscription, payments will be = 0.75 + 0.20 = 0.75 + 0.20 x 1

And for third subscription, payments will be = 0.75 + 0.20 = 0.75 + 0.20 x 2

Generalizing for nth subscription we get

Payments for nth subscription = 0.75 + 0.20(n-1)

so here we can see that arithmetic sequence is formed, having first term

and common difference = d = 0.20  

We need to determine sum of above arithmetic sequence for n = 175

Formula for sum of arithmetic sequence is as follows

In our case n = 175, a = 0.75, d = 0.20

Hence money earn by selling 175 magazine subscriptions will be 3176.25