Mark saved $10 each day and Julie saved $
k more than Mark each day. After 4 weeks, they were still short of $28 to buy a mobile phone.
- How much did the mobile phone cost? Express your answer in terms of k.
- If k = $19, how much did the mobile phone cost?
(a)
Amount Mark saved per day = $10
Amount Julie saved per day = $(10 +
k)
Total amount both saved per day
= 10 + 10 +
k = $(20 +
k)
Number of days in 4 weeks
= 4 x 7
= 28
Total both saved in 4 weeks
= 28(20 +
k)
= 28 x 20 + 28 x
k = $(560 + 28
k)
Cost of the mobile phone
= 560 + 28
k + 28
= 560 + 28 + 28
k= $(588 + 28
k)
(b)
If
k = $19,
Cost of the mobile phone
= 588 + 28 x 19
= 588 + 532
= $1120
Answer(s): (a) $(588 + 28
k) or $(28
k + 588); (b) $1120
