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

1. What was the percentage increase in the number of pencils sold from Aug to Sep?
2. There were 33 more pencils sold in Jul than in Aug. How many pencils were sold in Sep?
3. The average number of pencils sold from Jul to Nov was 115. What was the average number of pencils sold in Oct and Nov?

(a)
Percentage increase in the number of pencils 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 → 33

1 interval → 33 ÷ 3 = 11

Number of pencils sold in Sep
= 8 intervals
= 8 x 11
= 88

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

Total number of pencils sold from Jul to Sep
= 15 intervals
= 15 x 11
= 165

Total number of pencils sold from Jul to Nov
= 5 x 115
= 575

Number of pencils sold from Oct to Nov
= 575 - 165
= 410

Average number of pencils sold in Oct and Nov
= 410 ÷ 2
= 205

Answer(s): (a) 300%; (b) 88; (c) 205