Solving unknown

Question

A local Ace Hardware sells batteries ($4) and small boxes of pens ($3). In August, total sales were $960. Customers bought 3 times as many batteries as boxes of pens. How many of each did Ace Hardware sell?

Answer 1

4B + 3P = 960

B =3P

4B + B = 960

5B = 960

B = 960/5 = 192 batteries

P = B/3 = 192/3 = 64 pens

4(192) + 3(64) = 768 + 192 = 960