PSLE
The pie charts show the number of each type of stationery in 2 stationery boxes, C and D. The total number of stationery in Box C is thrice the total number of stationery in Box D.

1. Find the percentage of post-it pads in Box C.
2. What fraction of stationery in Box D is post-it pads?
3. The number of post-it pads in Box C is 405. Find the number of post-it pads in Box D.

(a)
^90°_360° = 25% of stationery in Box C

Percentage of rulers in Box C = 25%

Percentage of post-it pads in Box C
= 100% - 30% - 25%
= 45%

(b)
Percentage of post-it pads in Box D
= 100% - 60% - 30%
= 10%

Fraction of stationery in Box D that is post-it pads
= ¹₁₀

(c)
45% of stationery in Box C = 405
1% of stationery in Box C = 405 ÷ 45 = 9 
100% of the stationery in Box C = 100 x 9 = 900

Number of stationery in Box D
= 900 ÷ 3
= 300

100% of stationery in Box D = 300
1% of stationery in Box C = 300 ÷ 100 = 3
10% of stationery in Box C = 10 x 3 = 30  

Number of post-it pads in Box D = 30

Answer(s): (a) 45%; (b) ¹₁₀; (c) 30