PSLE
The bar graph shows the number of glues sold from Jul to Sep. The number of glues sold is not shown on the scale.

1. What was the percentage decrease in the number of glues sold from Jul to Aug?
2. There were 76 more glues sold in Sep than in Jul. How many glues were sold in Sep?
3. The average number of glues sold from Jul to Nov was 127. What was the average number of glues sold in Oct and Nov?

(a)
Percentage decrease in the number of glues from Jul to Aug
= ^{5 - 3}₅ x 100%
= ²₅ x 100%
= 40%

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

4 intervals → 76

1 interval → 76 ÷ 4 = 19

Number of glues sold in Sep
= 9 intervals
= 9 x 19
= 171

(c)
Total intervals from Jul to Sep
= 5 + 3 + 9
= 17

Total number of glues sold from Jul to Sep
= 17 intervals
= 17 x 19
= 323

Total number of glues sold from Jul to Nov
= 5 x 127
= 635

Number of glues sold from Oct to Nov
= 635 - 323
= 312

Average number of glues sold in Oct and Nov
= 312 ÷ 2
= 156

Answer(s): (a) 40%; (b) 171; (c) 156