Ethan saved $11 each day and Risa saved $
b more than Ethan each day. After 3 weeks, they were still short of $30 to buy a laptop.
- How much did the laptop cost? Express your answer in terms of b.
- If b = $3, how much did the laptop cost?
(a)
Amount Ethan saved per day = $11
Amount Risa saved per day = $(11 +
b)
Total amount both saved per day
= 11 + 11 +
b = $(22 +
b)
Number of days in 3 weeks
= 3 x 7
= 21
Total both saved in 3 weeks
= 21(22 +
b)
= 21 x 22 + 21 x
b = $(462 + 21
b)
Cost of the laptop
= 462 + 21
b + 30
= 462 + 30 + 21
b= $(492 + 21
b)
(b)
If
b = $3,
Cost of the laptop
= 492 + 21 x 3
= 492 + 63
= $555
Answer(s): (a) $(492 + 21
b) or $(21
b + 492); (b) $555
