John saved $10 each day and Yoko saved $
x more than John each day. After 2 weeks, they were still short of $29 to buy a mobile phone.
- How much did the mobile phone cost? Express your answer in terms of x.
- If x = $19, how much did the mobile phone cost?
(a)
Amount John saved per day = $10
Amount Yoko saved per day = $(10 +
x)
Total amount both saved per day
= 10 + 10 +
x = $(20 +
x)
Number of days in 2 weeks
= 2 x 7
= 14
Total both saved in 2 weeks
= 14(20 +
x)
= 14 x 20 + 14 x
x = $(280 + 14
x)
Cost of the mobile phone
= 280 + 14
x + 29
= 280 + 29 + 14
x= $(309 + 14
x)
(b)
If
x = $19,
Cost of the mobile phone
= 309 + 14 x 19
= 309 + 266
= $575
Answer(s): (a) $(309 + 14
x) or $(14
x + 309); (b) $575
