Carl saved $10 each day and Risa saved $
p more than Carl each day. After 2 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 p.
- If p = $7, how much did the mobile phone cost?
(a)
Amount Carl saved per day = $10
Amount Risa saved per day = $(10 +
p)
Total amount both saved per day
= 10 + 10 +
p = $(20 +
p)
Number of days in 2 weeks
= 2 x 7
= 14
Total both saved in 2 weeks
= 14(20 +
p)
= 14 x 20 + 14 x
p = $(280 + 14
p)
Cost of the mobile phone
= 280 + 14
p + 30
= 280 + 30 + 14
p= $(310 + 14
p)
(b)
If
p = $7,
Cost of the mobile phone
= 310 + 14 x 7
= 310 + 98
= $408
Answer(s): (a) $(310 + 14
p) or $(14
p + 310); (b) $408
