Will saved $9 each day and Eva saved $
j more than Will each day. After 4 weeks, they were still short of $30 to buy a mobile phone.
- How much did the mobile phone cost? Express your answer in terms of j.
- If j = $14, how much did the mobile phone cost?
(a)
Amount Will saved per day = $9
Amount Eva saved per day = $(9 +
j)
Total amount both saved per day
= 9 + 9 +
j = $(18 +
j)
Number of days in 4 weeks
= 4 x 7
= 28
Total both saved in 4 weeks
= 28(18 +
j)
= 28 x 18 + 28 x
j = $(504 + 28
j)
Cost of the mobile phone
= 504 + 28
j + 30
= 504 + 30 + 28
j= $(534 + 28
j)
(b)
If
j = $14,
Cost of the mobile phone
= 534 + 28 x 14
= 534 + 392
= $926
Answer(s): (a) $(534 + 28
j) or $(28
j + 534); (b) $926
