RRB Assistant Loco Pilot and Technician Model Paper 16 with key

Question : 56 of 75

Marks: +1, -0

The average mathematics marks of two sections A and B of class IX in the annual examination is 74. The average marks of section A is 77.5 and that of Section B is 70. The ratio of the number of students of section A and B is:

7 : 8
7 : 5
8 : 7
8 : 5

Validate

Solution:

If the number of students in sectionA be x and that in section Bby y, then
74 =

{77.5×x+y×70}/{x+y}

⇒ 74x + 74y = 77.5x + 70y
⇒ 77.5x – 74x = 74y – 70y
⇒ 3.5 x = 4y
⇒

x/y

4/{3.5}

8/7

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