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

1. What was the percentage increase in the number of staplers sold from Jan to Feb?
2. There were 88 less staplers sold in Jan than in Mar. How many staplers were sold in Jan?
3. The average number of staplers sold from Jan to May was 159. What was the average number of staplers sold in Apr and May?

(a)
Percentage increase in the number of staplers 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 → 88

1 interval → 88 ÷ 8 = 11

Number of staplers sold in Jan
= 2 intervals
= 2 x 11
= 22

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

Total number of staplers sold from Jan to Mar
= 17 intervals
= 17 x 11
= 187

Total number of staplers sold from Jan to May
= 5 x 159
= 795

Number of staplers sold from Apr to May
= 795 - 187
= 608

Average number of staplers sold in Apr and May
= 608 ÷ 2
= 304

Answer(s): (a) 150%; (b) 22; (c) 304