PSLE
Linda spent $110 in October. This amount was a 45% decrease from what she spent in September. The amount she spent in November was a 20% increase from what she spent in October.

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

	Spending
September	100%
Change	- 45%
October	55%	100 u
Change		+ 20 u
November		120 u

(a)
Spending in September = 100%
Spending in October = 100% - 45% = 55%

55% = 110

1% = 110 ÷ 55 = 2

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

Spending in October = 100 u
Spending in November = 100 u + 20 u = 120 u 

100 u = 110

1 u = 110 ÷ 100 = 1.1

Spending in November
= 120 u
= 120 x 1.1
= $132

Total spending from September to November
= 200 + 110 + 132
= $442

(b)
Decrease in spending in November compared to September
= 200 - 132 
= $68

Percentage decrease
= ^{Decrease in spending}_{Spending in September} x 100%
= ⁶⁸₂₀₀ x 100%
= 34%

Answer(s): (a) $442; (b) 34%