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

1. What was the percentage increase in the number of correction tapes sold from Aug to Sep?
2. There were 54 more correction tapes sold in Jul than in Aug. How many correction tapes were sold in Sep?
3. The average number of correction tapes sold from Jul to Nov was 132. What was the average number of correction tapes sold in Oct and Nov?

(a)
Percentage increase in the number of correction tapes 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 → 54

1 interval → 54 ÷ 3 = 18

Number of correction tapes sold in Sep
= 8 intervals
= 8 x 18
= 144

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

Total number of correction tapes sold from Jul to Sep
= 15 intervals
= 15 x 18
= 270

Total number of correction tapes sold from Jul to Nov
= 5 x 132
= 660

Number of correction tapes sold from Oct to Nov
= 660 - 270
= 390

Average number of correction tapes sold in Oct and Nov
= 390 ÷ 2
= 195

Answer(s): (a) 300%; (b) 144; (c) 195