PSLE
The bar graph shows the number of highlighters sold from Jan to Mar. The number of highlighters sold is not shown on the scale.

1. What was the percentage increase in the number of highlighters sold from Jan to Feb?
2. There were 112 less highlighters sold in Jan than in Mar. How many highlighters were sold in Jan?
3. The average number of highlighters sold from Jan to May was 132. What was the average number of highlighters sold in Apr and May?

(a)
Percentage increase in the number of highlighters from Jan to Feb
= ^{5 - 2}₂ x 100%
= ³₂ x 100%
= 150%

(b)
Difference in intervals between Mar and Jan
= 10 - 2
= 8

8 intervals → 112

1 interval → 112 ÷ 8 = 14

Number of highlighters sold in Jan
= 2 intervals
= 2 x 14
= 28

(c)
Total intervals from Jan to Mar
= 2 + 5 + 10
= 17

Total number of highlighters sold from Jan to Mar
= 17 intervals
= 17 x 14
= 238

Total number of highlighters sold from Jan to May
= 5 x 132
= 660

Number of highlighters sold from Apr to May
= 660 - 238
= 422

Average number of highlighters sold in Apr and May
= 422 ÷ 2
= 211

Answer(s): (a) 150%; (b) 28; (c) 211