Hi Joshua,

112 - 98 = 14 and 98 - 84 = 14 so the common difference for this arithmetic progression is 14.

The first term is 112, the $2^{nd}$ term is 112 minus 14, the $3^{rd}$ term is 112 minus 2 times 14, the $4^{th}$ term is 112 minus 3 times 14, and so on. How many times do you subtract 14 to arrive at the $50^{th}$ term? What is the $50^{th}$ term?

To calculate the sum look at my response to a question from Tim.

Penny