SSC CGL 17 Aug 2021 Shift 1 Paper

Question : 70 of 100

Marks: +1, -0

The average of 8 consecutive even numbers written in ascending order is 17 . What is the average of the last three numbers, 36 and 53 ?

Solution:

Let 8 consecutive even numbers are

x, x+2, x+4, x+6, x+8

x+10, x+12

and

x+14

According to the question,

x+x+2+x+4+x+6+x

\;{+8+x+10+x+12+x+14}/{8}=17

⇒ \;\; 8 x+56=136

⇒ \;\; 8 x=136-56=80

x=\;{80}/{8}=10

Average of last 3 numbers, 36 and 53

\;\; =\;{x+10+x+12+x+14+36+53}/{5}

\;\; =\;{3 × 10+125}/{5}=\;{30+125}/{5}=\;{155}/{5}=31

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