PSLE
Linda saved $180 in October. This amount was a 10% decrease from what she saved in September. The amount she saved in November was a 10% increase from what she saved in October.

1. What was the total amount that Linda saved from September to November?
2. What was the percentage decrease in the amount Linda saved in November compared to September?

	Savings
September	100%
Change	- 10%
October	90%	100 u
Change		+ 10 u
November		110 u

(a)
Savings in September = 100%
Savings in October = 100% - 10% = 90%

90% = 180

1% = 180 ÷ 90 = 2

Savings in September
= 100% 
= 100 x 2
= $200

Savings in October = 100 u
Savings in November = 100 u + 10 u = 110 u 

100 u = 180

1 u = 180 ÷ 100 = 1.8

Savings in November
= 110 u
= 110 x 1.8
= $198

Total savings from September to November
= 200 + 180 + 198
= $578

(b)
Decrease in savings in November compared to September
= 200 - 198 
= $2

Percentage decrease
= ^{Decrease in savings}_{Savings in September} x 100%
= ²₂₀₀ x 100%
= 1%

Answer(s): (a) $578; (b) 1%