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    Question

    The average height of the boys in a class is 160 cm,

    while the average height of the girls is 155 cm. The overall average height of all students in the class is 157 cm, and the total number of students is 180. Can you determine how many boys are there in the class?
    A 108 Correct Answer Incorrect Answer
    B 66 Correct Answer Incorrect Answer
    C 72 Correct Answer Incorrect Answer
    D 84 Correct Answer Incorrect Answer

    Solution

    Let number of boys in the class be ‘b’ and number of girls in the class be ‘180 – b’. ATQ; {160 × b + 155 × (180 – b)}/180 = 157 Or, (160b + 155 × 180 – 155b) = 157 × 180 Or, 160b – 155b = 2 × 180 Or, 5b = 360 Or, b = 72 Therefore, number of boys in the class are 72.

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