Jeremy saved $11 each day and Xuan saved $
z more than Jeremy each day. After 3 weeks, they were still short of $30 to buy a stereo system.
- How much did the stereo system cost? Express your answer in terms of z.
- If z = $7, how much did the stereo system cost?
(a)
Amount Jeremy saved per day = $11
Amount Xuan saved per day = $(11 +
z)
Total amount both saved per day
= 11 + 11 +
z = $(22 +
z)
Number of days in 3 weeks
= 3 x 7
= 21
Total both saved in 3 weeks
= 21(22 +
z)
= 21 x 22 + 21 x
z = $(462 + 21
z)
Cost of the stereo system
= 462 + 21
z + 30
= 462 + 30 + 21
z= $(492 + 21
z)
(b)
If
z = $7,
Cost of the stereo system
= 492 + 21 x 7
= 492 + 147
= $639
Answer(s): (a) $(492 + 21
z) or $(21
z + 492); (b) $639
