PSLE
School camp coats were available in 4 colours: green, pink, black and red. At the camp, each pupils chose one coat. The pie chart represents the pupils' choice of coat colours. 40 pupils chose red coats. The pupils' choice of coat colours is also represented by the bar graph. The bar that shows the number of pupils who chose green coats has not been drawn. How many pupils chose green coats?

    
From the pie graph,
fraction of pupils who chose black or pink
= ^90°_360°
= ¹₄

From the bar graph,
Number of pupils who chose black = Number of pupils who chose pink = 40 

¹₄ of the pie chart = 40
⁴₄ of the pie chart = 4 x 40 = 160

Total number of pupils = 160

Number of pupils who chose green coats
= 160 - 40 - 40 - 40
= 40

Answer(s): 40