Question
In a class, the number of girls is 20% more than that of
boys. The number of students in the class is 88. In a mathematics test, the average score of boys is 30% more than that of girls. If the average score of all the students is 75, then what is the average score of the boys?Solution
Let the number of boys be x. Then, the number of girls is 1.2x. Given:  x+1.2x=88 x=40 (boys), 1.2x=48 (girls)  Let the average score of girls be g, and boys be b = 1.3g. Total score equation: 40b+48g=6600 =40×1.3g+48g =6600 52g+48g=6600 100g =6600 g=66 So, b=1.3 x 66 = 85.8. Thus, the average score of boys is 85.8.
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