PSLE
The pie charts show the number of each type of stationery in 2 stationery boxes, M and N. The total number of stationery in Box M is four times the total number of stationery in Box N.

1. Find the percentage of folders in Box M.
2. What fraction of stationery in Box N is folders?
3. The number of folders in Box M is 160. Find the number of folders in Box N.

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

Percentage of post-it pads in Box M = 25%

Percentage of folders in Box M
= 100% - 55% - 25%
= 20%

(b)
Percentage of folders in Box N
= 100% - 60% - 25%
= 15%

Fraction of stationery in Box N that is folders
= ³₂₀

(c)
20% of stationery in Box M = 160
1% of stationery in Box M = 160 ÷ 20 = 8 
100% of the stationery in Box M = 100 x 8 = 800

Number of stationery in Box N
= 800 ÷ 4
= 200

100% of stationery in Box N = 200
1% of stationery in Box M = 200 ÷ 100 = 2
15% of stationery in Box M = 15 x 2 = 30  

Number of folders in Box N = 30

Answer(s): (a) 20%; (b) ³₂₀; (c) 30