Archie saved $9 each day and Sarah saved $
a more than Archie each day. After 2 weeks, they were still short of $28 to buy a hi-fi system.
- How much did the hi-fi system cost? Express your answer in terms of a.
- If a = $7, how much did the hi-fi system cost?
(a)
Amount Archie saved per day = $9
Amount Sarah saved per day = $(9 +
a)
Total amount both saved per day
= 9 + 9 +
a = $(18 +
a)
Number of days in 2 weeks
= 2 x 7
= 14
Total both saved in 2 weeks
= 14(18 +
a)
= 14 x 18 + 14 x
a = $(252 + 14
a)
Cost of the hi-fi system
= 252 + 14
a + 28
= 252 + 28 + 14
a= $(280 + 14
a)
(b)
If
a = $7,
Cost of the hi-fi system
= 280 + 14 x 7
= 280 + 98
= $378
Answer(s): (a) $(280 + 14
a) or $(14
a + 280); (b) $378
