David saved $8 each day and Xylium saved $
b more than David each day. After 3 weeks, they were still short of $29 to buy a laptop.
- How much did the laptop cost? Express your answer in terms of b.
- If b = $19, how much did the laptop cost?
(a)
Amount David saved per day = $8
Amount Xylium saved per day = $(8 +
b)
Total amount both saved per day
= 8 + 8 +
b = $(16 +
b)
Number of days in 3 weeks
= 3 x 7
= 21
Total both saved in 3 weeks
= 21(16 +
b)
= 21 x 16 + 21 x
b = $(336 + 21
b)
Cost of the laptop
= 336 + 21
b + 29
= 336 + 29 + 21
b= $(365 + 21
b)
(b)
If
b = $19,
Cost of the laptop
= 365 + 21 x 19
= 365 + 399
= $764
Answer(s): (a) $(365 + 21
b) or $(21
b + 365); (b) $764
