PSLE The bar graph shows the number of foolscaps sold from Jul to Sep. The number of foolscaps sold is not shown on the scale.
- What was the percentage decrease in the number of foolscaps sold from Aug to Sep?
- There were 133 more foolscaps sold in Sep than in Jul. How many foolscaps were sold in Aug?
- The average number of foolscaps sold from Jul to Nov was 159. What was the average number of foolscaps sold in Oct and Nov?
(a)
Percentage decrease in the number of foolscaps from Aug to Sep
=
10 - 810 x 100%
=
210 x 100%
= 20%
(b)
Difference in the number of intervals between Sep and Jul
= 8 - 1
= 7
7 intervals → 133
1 interval → 133 ÷ 7 = 19
Number of foolscaps sold in Aug
= 10 intervals
= 10 x 19
= 190
(c)
Total intervals from Jul to Sep
= 1 + 10 + 8
= 19
Total number of foolscaps sold from Jul to Sep
= 19 intervals
= 19 x 19
= 361
Total number of foolscaps sold from Jul to Nov
= 5 x 159
= 795
Number of foolscaps sold from Oct to Nov
= 795 - 361
= 434
Average number of foolscaps sold in Oct and Nov
= 434 ÷ 2
= 217
Answer(s): (a) 20%; (b) 190; (c) 217