PSLE
School camp vests were available in 4 colours: gold, black, blue and purple. At the camp, each contestants chose one vest. The pie chart represents the contestants' choice of vest colours. 38 contestants chose gold vests. The contestants' choice of vest colours is also represented by the bar graph. The bar that shows the number of contestants who chose black vests has not been drawn. How many contestants chose black vests?

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

From the bar graph,
Number of contestants who chose blue = Number of contestants who chose purple = 57 

¹₄ of the pie chart = 57
⁴₄ of the pie chart = 4 x 57 = 228

Total number of contestants = 228

Number of contestants who chose black vests
= 228 - 57 - 57 - 38
= 76

Answer(s): 76