Practice Test Discussion

Q)

The average height of 16 students is 142 cm. If the height of the teacher is included, the average height increases by 1 cm. The height of the teacher is

[Corporation Bank, 2009]


  • Explanation

    Here we can use the formula

    Average (A)=Sum of observations (S)No. of observations (N) ⇒ S=A×N

    According to the question,

    Sum of height of 16 students (A=142, N=16)

    ⇒S=142 X 16 =2272

    Later, the height of the teacher included, the average height increases by 1 cm. (so A=143, N=17)

    So, sum of height of 16 students and a teacher

    ⇒S=143 X 17 =2431

    Now,

    Height of the teacher =(sum of height of 16 students)-(Sum of height of 16 students and a teacher)

    =2431-2272

    = 159 cm.

    Hence, Option B is correct.

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    Average

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