Jeremy saved $10 each day and Erika saved $
j more than Jeremy each day. After 3 weeks, they were still short of $30 to buy a hard drive.
- How much did the hard drive cost? Express your answer in terms of j.
- If j = $13, how much did the hard drive cost?
(a)
Amount Jeremy saved per day = $10
Amount Erika saved per day = $(10 +
j)
Total amount both saved per day
= 10 + 10 +
j = $(20 +
j)
Number of days in 3 weeks
= 3 x 7
= 21
Total both saved in 3 weeks
= 21(20 +
j)
= 21 x 20 + 21 x
j = $(420 + 21
j)
Cost of the hard drive
= 420 + 21
j + 30
= 420 + 30 + 21
j= $(450 + 21
j)
(b)
If
j = $13,
Cost of the hard drive
= 450 + 21 x 13
= 450 + 273
= $723
Answer(s): (a) $(450 + 21
j) or $(21
j + 450); (b) $723
