PSLE Linda spent $490 in November. This amount was a 30% decrease from what she spent in October. The amount she spent in December was a 10% increase from what she spent in November.
- What was the total amount that Linda spent from October to December?
- What was the percentage decrease in the amount Linda spent in December compared to October?
|
Spending |
October |
100% |
|
Change |
- 30% |
|
November |
70% |
100 u |
Change |
|
+ 10 u |
December |
|
110 u |
(a)
Spending in October = 100%
Spending in November = 100% - 30% = 70%
70% = 490
1% = 490 ÷ 70 = 7
Spending in October
= 100%
= 100 x 7
= $700
Spending in November = 100 u
Spending in December = 100 u + 10 u = 110 u
100 u = 490
1 u = 490 ÷ 100 = 4.9
Spending in December
= 110 u
= 110 x 4.9
= $539
Total spending from October to December
= 700 + 490 + 539
= $1729
(b)
Decrease in spending in December compared to October
= 700 - 539
= $161
Percentage decrease
=
Decrease in spendingSpending in October x 100%
=
161700 x 100%
= 23%
Answer(s): (a) $1729; (b) 23%