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

1. What was the percentage increase in the number of markers sold from Aug to Sep?
2. There were 42 more markers sold in Jul than in Aug. How many markers were sold in Sep?
3. The average number of markers sold from Jul to Nov was 130. What was the average number of markers sold in Oct and Nov?

(a)
Percentage increase in the number of markers 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 → 42

1 interval → 42 ÷ 3 = 14

Number of markers sold in Sep
= 8 intervals
= 8 x 14
= 112

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

Total number of markers sold from Jul to Sep
= 15 intervals
= 15 x 14
= 210

Total number of markers sold from Jul to Nov
= 5 x 130
= 650

Number of markers sold from Oct to Nov
= 650 - 210
= 440

Average number of markers sold in Oct and Nov
= 440 ÷ 2
= 220

Answer(s): (a) 300%; (b) 112; (c) 220