PSLE Linda spent $300 in October. This amount was a 40% decrease from what she spent in September. The amount she spent in November was a 40% increase from what she spent in October.
- What was the total amount that Linda spent from September to November?
- What was the percentage decrease in the amount Linda spent in November compared to September?
|
Spending |
September |
100% |
|
Change |
- 40% |
|
October |
60% |
100 u |
Change |
|
+ 40 u |
November |
|
140 u |
(a)
Spending in September = 100%
Spending in October = 100% - 40% = 60%
60% = 300
1% = 300 ÷ 60 = 5
Spending in September
= 100%
= 100 x 5
= $500
Spending in October = 100 u
Spending in November = 100 u + 40 u = 140 u
100 u = 300
1 u = 300 ÷ 100 = 3
Spending in November
= 140 u
= 140 x 3
= $420
Total spending from September to November
= 500 + 300 + 420
= $1220
(b)
Decrease in spending in November compared to September
= 500 - 420
= $80
Percentage decrease
=
Decrease in spendingSpending in September x 100%
=
80500 x 100%
= 16%
Answer(s): (a) $1220; (b) 16%