PSLE
The bar graph shows the number of post-it pads sold from Jan to Mar. The number of post-it pads sold is not shown on the scale.

1. What was the percentage decrease in the number of post-it pads sold from Jan to Feb?
2. There were 60 more post-it pads sold in Mar than in Jan. How many post-it pads were sold in Mar?
3. The average number of post-it pads sold from Jan to May was 135. What was the average number of post-it pads sold in Apr and May?

(a)
Percentage decrease in the number of post-it pads 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 → 60

1 interval → 60 ÷ 4 = 15

Number of post-it pads sold in Mar
= 9 intervals
= 9 x 15
= 135

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

Total number of post-it pads sold from Jan to Mar
= 17 intervals
= 17 x 15
= 255

Total number of post-it pads sold from Jan to May
= 5 x 135
= 675

Number of post-it pads sold from Apr to May
= 675 - 255
= 420

Average number of post-it pads sold in Apr and May
= 420 ÷ 2
= 210

Answer(s): (a) 40%; (b) 135; (c) 210