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

1. What was the percentage increase in the number of files sold from Jan to Feb?
2. There were 104 less files sold in Jan than in Mar. How many files were sold in Jan?
3. The average number of files sold from Jan to May was 167. What was the average number of files sold in Apr and May?

(a)
Percentage increase in the number of files 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 → 104

1 interval → 104 ÷ 8 = 13

Number of files sold in Jan
= 2 intervals
= 2 x 13
= 26

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

Total number of files sold from Jan to Mar
= 17 intervals
= 17 x 13
= 221

Total number of files sold from Jan to May
= 5 x 167
= 835

Number of files sold from Apr to May
= 835 - 221
= 614

Average number of files sold in Apr and May
= 614 ÷ 2
= 307

Answer(s): (a) 150%; (b) 26; (c) 307