PSLE Linda spent $1100 in October. This amount was a 10% increase from what she spent in September. The amount she spent in November was a 20% decrease 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 |
+ 10% |
|
October |
110% |
100 u |
Change |
|
- 20 u |
November |
|
80 u |
(a)
Spending in September = 100%
Spending in October = 100% + 10% = 110%
110% = 1100
1% = 1100 ÷ 110 = 10
Spending in September
= 100%
= 100 x 10
= $1000
Spending in October = 100 u
Spending in November = 100 u - 20 u = 80 u
100 u = 1100
1 u = 1100 ÷ 100 = 11
Spending in November
= 80 u
= 80 x 11
= $880
Total spending from September to November
= 1000 + 1100 + 880
= $2980
(b)
Decrease in spending in November compared to September
= 1000 - 880
= $120
Percentage decrease
=
Decrease in spendingSpending in September x 100%
=
1201000 x 100%
= 12%
Answer(s): (a) $2980; (b) 12%