PSLE Linda spent $600 in October. This amount was a 25% decrease from what she spent in September. The amount she spent in November was a 20% 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 |
- 25% |
|
October |
75% |
100 u |
Change |
|
+ 20 u |
November |
|
120 u |
(a)
Spending in September = 100%
Spending in October = 100% - 25% = 75%
75% = 600
1% = 600 ÷ 75 = 8
Spending in September
= 100%
= 100 x 8
= $800
Spending in October = 100 u
Spending in November = 100 u + 20 u = 120 u
100 u = 600
1 u = 600 ÷ 100 = 6
Spending in November
= 120 u
= 120 x 6
= $720
Total spending from September to November
= 800 + 600 + 720
= $2120
(b)
Decrease in spending in November compared to September
= 800 - 720
= $80
Percentage decrease
=
Decrease in spendingSpending in September x 100%
=
80800 x 100%
= 10%
Answer(s): (a) $2120; (b) 10%