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

    
From the pie graph,
fraction of students who chose green or brown
= ^90°_360°
= ¹₄

From the bar graph,
Number of students who chose green = Number of students who chose brown = 60 

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

Total number of students = 240

Number of students who chose blue blazers
= 240 - 60 - 60 - 40
= 80

Answer(s): 80