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

    
From the pie graph,
fraction of contestants who chose yellow or red
= ^90°_360°
= ¹₄

From the bar graph,
Number of contestants who chose yellow = Number of contestants who chose red = 40 

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

Total number of contestants = 160

Number of contestants who chose green shirts
= 160 - 40 - 40 - 40
= 40

Answer(s): 40