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

1. What was the percentage decrease in the number of rulers sold from Jan to Feb?
2. There were 68 more rulers sold in Mar than in Jan. How many rulers were sold in Mar?
3. The average number of rulers sold from Jan to May was 181. What was the average number of rulers sold in Apr and May?

(a)
Percentage decrease in the number of rulers from Jan to Feb
= ^{5 - 3}₅ x 100%
= ²₅ x 100%
= 40%

(b)
Difference in the number of intervals between Mar and Jan
= 9 - 5
= 4

4 intervals → 68

1 interval → 68 ÷ 4 = 17

Number of rulers sold in Mar
= 9 intervals
= 9 x 17
= 153

(c)
Total intervals from Jan to Mar
= 5 + 3 + 9
= 17

Total number of rulers sold from Jan to Mar
= 17 intervals
= 17 x 17
= 289

Total number of rulers sold from Jan to May
= 5 x 181
= 905

Number of rulers sold from Apr to May
= 905 - 289
= 616

Average number of rulers sold in Apr and May
= 616 ÷ 2
= 308

Answer(s): (a) 40%; (b) 153; (c) 308