PSLE
School camp t-shirts were available in 4 colours: red, gold, green and yellow. At the camp, each participants chose one t-shirt. The pie chart represents the participants' choice of t-shirt colours. 30 participants chose gold t-shirts. The participants' choice of t-shirt colours is also represented by the bar graph. The bar that shows the number of participants who chose green t-shirts has not been drawn. How many participants chose green t-shirts?

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

From the bar graph,
Number of participants who chose red = Number of participants who chose yellow = 60 

¹₄ of the pie chart = 60
⁴₄ of the pie chart = 4 x 60 = 240

Total number of participants = 240

Number of participants who chose green t-shirts
= 240 - 60 - 60 - 30
= 90

Answer(s): 90