New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    In a school, the average height of the students of the

    tenth standard is 100 cm. The average height of boys is 118 cm. whereas the average height of girls is 95 cm. What is the number of girls in the class if there are 20 boys?
    A 72 Correct Answer Incorrect Answer
    B 63 Correct Answer Incorrect Answer
    C 54 Correct Answer Incorrect Answer
    D 36 Correct Answer Incorrect Answer

    Solution

    Average of total students' height =100cm. Average of 20boys height =118 Total height of 20 boys =118×20=2360cm Average of girls =95cm Let the number of Girls =x So the total height of x girls =95xcm. ATQ- (2360+95x)/20+x =100 2360+95x =2000+100x 5x =360 X =72.

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