PSLE Linda spent $320 in August. This amount was a 20% decrease from what she spent in July. The amount she spent in September was a 15% increase from what she spent in August.
- What was the total amount that Linda spent from July to September?
- What was the percentage decrease in the amount Linda spent in September compared to July?
|
Spending |
July |
100% |
|
Change |
- 20% |
|
August |
80% |
100 u |
Change |
|
+ 15 u |
September |
|
115 u |
(a)
Spending in July = 100%
Spending in August = 100% - 20% = 80%
80% = 320
1% = 320 ÷ 80 = 4
Spending in July
= 100%
= 100 x 4
= $400
Spending in August = 100 u
Spending in September = 100 u + 15 u = 115 u
100 u = 320
1 u = 320 ÷ 100 = 3.2
Spending in September
= 115 u
= 115 x 3.2
= $368
Total spending from July to September
= 400 + 320 + 368
= $1088
(b)
Decrease in spending in September compared to July
= 400 - 368
= $32
Percentage decrease
=
Decrease in spendingSpending in July x 100%
=
32400 x 100%
= 8%
Answer(s): (a) $1088; (b) 8%