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

1. What was the percentage increase in the number of pens sold from Feb to Mar?
2. There were 39 more pens sold in Jan than in Feb. How many pens were sold in Mar?
3. The average number of pens sold from Jan to May was 125. What was the average number of pens sold in Apr and May?

(a)
Percentage increase in the number of pens sold from Feb to Mar
= ^{8 - 2}₂ x 100%
= ⁶₂ x 100%
= 300%

(b)
Difference in intervals between Jan and Feb
= 5 - 2
= 3

3 intervals → 39

1 interval → 39 ÷ 3 = 13

Number of pens sold in Mar
= 8 intervals
= 8 x 13
= 104

(c)
Total intervals from Jan to Mar
= 5 + 2 + 8
= 15

Total number of pens sold from Jan to Mar
= 15 intervals
= 15 x 13
= 195

Total number of pens sold from Jan to May
= 5 x 125
= 625

Number of pens sold from Apr to May
= 625 - 195
= 430

Average number of pens sold in Apr and May
= 430 ÷ 2
= 215

Answer(s): (a) 300%; (b) 104; (c) 215