How much will Andrew earn over the course of 10 weeks?
Use Arithmetic Series formula:
S = N / 2 [2F + (N - 1) x D]
S = 10 /2 [2*4 + (10 - 1) x 13]
S = 5 [8 + (9) x 13]
S = 5 [8 + 117]
S = 5[125]
S =$625 - what Andrew will earn in allowance over a period of 10 weeks.
