PSLE Linda saved $320 in October. This amount was a 20% decrease from what she saved in September. The amount she saved in November was a 20% increase from what she saved in October.
- What was the total amount that Linda saved from September to November?
- What was the percentage decrease in the amount Linda saved in November compared to September?
|
Savings |
September |
100% |
|
Change |
- 20% |
|
October |
80% |
100 u |
Change |
|
+ 20 u |
November |
|
120 u |
(a)
Savings in September = 100%
Savings in October = 100% - 20% = 80%
80% = 320
1% = 320 ÷ 80 = 4
Savings in September
= 100%
= 100 x 4
= $400
Savings in October = 100 u
Savings in November = 100 u + 20 u = 120 u
100 u = 320
1 u = 320 ÷ 100 = 3.2
Savings in November
= 120 u
= 120 x 3.2
= $384
Total savings from September to November
= 400 + 320 + 384
= $1104
(b)
Decrease in savings in November compared to September
= 400 - 384
= $16
Percentage decrease
=
Decrease in savingsSavings in September x 100%
=
16400 x 100%
= 4%
Answer(s): (a) $1104; (b) 4%