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

1. What was the percentage increase in the number of staplers sold from Aug to Sep?
2. There were 45 more staplers sold in Jul than in Aug. How many staplers were sold in Sep?
3. The average number of staplers sold from Jul to Nov was 119. What was the average number of staplers sold in Oct and Nov?

(a)
Percentage increase in the number of staplers sold from Aug to Sep
= ^{8 - 2}₂ x 100%
= ⁶₂ x 100%
= 300%

(b)
Difference in intervals between Jul and Aug
= 5 - 2
= 3

3 intervals → 45

1 interval → 45 ÷ 3 = 15

Number of staplers sold in Sep
= 8 intervals
= 8 x 15
= 120

(c)
Total intervals from Jul to Sep
= 5 + 2 + 8
= 15

Total number of staplers sold from Jul to Sep
= 15 intervals
= 15 x 15
= 225

Total number of staplers sold from Jul to Nov
= 5 x 119
= 595

Number of staplers sold from Oct to Nov
= 595 - 225
= 370

Average number of staplers sold in Oct and Nov
= 370 ÷ 2
= 185

Answer(s): (a) 300%; (b) 120; (c) 185