PSLE Linda spent $160 in November. This amount was a 20% decrease from what she spent in October. The amount she spent in December was a 50% increase from what she spent in November.
- What was the total amount that Linda spent from October to December?
- What was the percentage increase in the amount Linda spent in December compared to October?
|
Spending |
October |
100% |
|
Change |
- 20% |
|
November |
80% |
100 u |
Change |
|
+ 50 u |
December |
|
150 u |
(a)
Spending in October = 100%
Spending in November = 100% - 20% = 80%
80% = 160
1% = 160 ÷ 80 = 2
Spending in October
= 100%
= 100 x 2
= $200
Spending in November = 100 u
Spending in December = 100 u + 50 u = 150 u
100 u = 160
1 u = 160 ÷ 100 = 1.6
Spending in December
= 150 u
= 150 x 1.6
= $240
Total spending from October to December
= 200 + 160 + 240
= $600
(b)
Increase in spending in December compared to October
= 240 - 200
= $40
Percentage increase
=
Increase in spendingSpending in October x 100%
=
40200 x 100%
= 20%
Answer(s): (a) $600; (b) 20%