PSLE
The bar graph shows the number of foolscaps sold from Jul to Sep. The number of foolscaps sold is not shown on the scale.

1. What was the percentage decrease in the number of foolscaps sold from Jul to Aug?
2. There were 40 more foolscaps sold in Sep than in Jul. How many foolscaps were sold in Sep?
3. The average number of foolscaps sold from Jul to Nov was 118. What was the average number of foolscaps sold in Oct and Nov?

(a)
Percentage decrease in the number of foolscaps from Jul to Aug
= ^{5 - 3}₅ x 100%
= ²₅ x 100%
= 40%

(b)
Difference in the number of intervals between Sep and Jul
= 9 - 5
= 4

4 intervals → 40

1 interval → 40 ÷ 4 = 10

Number of foolscaps sold in Sep
= 9 intervals
= 9 x 10
= 90

(c)
Total intervals from Jul to Sep
= 5 + 3 + 9
= 17

Total number of foolscaps sold from Jul to Sep
= 17 intervals
= 17 x 10
= 170

Total number of foolscaps sold from Jul to Nov
= 5 x 118
= 590

Number of foolscaps sold from Oct to Nov
= 590 - 170
= 420

Average number of foolscaps sold in Oct and Nov
= 420 ÷ 2
= 210

Answer(s): (a) 40%; (b) 90; (c) 210