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

1. What was the percentage increase in the number of pencils sold from Jan to Feb?
2. There were 88 less pencils sold in Jan than in Mar. How many pencils were sold in Jan?
3. The average number of pencils sold from Jan to May was 165. What was the average number of pencils sold in Apr and May?

(a)
Percentage increase in the number of pencils 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 pencils sold in Jan
= 2 intervals
= 2 x 11
= 22

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

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

Total number of pencils sold from Jan to May
= 5 x 165
= 825

Number of pencils sold from Apr to May
= 825 - 187
= 638

Average number of pencils sold in Apr and May
= 638 ÷ 2
= 319

Answer(s): (a) 150%; (b) 22; (c) 319