SSC CGL 6 06 2019 Shift 2 Paper

Question : 65 of 100

Marks: +1, -0

When x is subtracted from each of 21, 22, 60 and 64, the numbers so obtained, in this order, are in proportion. What is the mean proportional between (x + 1) and (7x + 8)?

Validate

Solution:

ATQ.

\ {21-x}/{22-x}=\ {60-x}/{64-x}

21 \× 64-21 x-64 x+x^{2}

=60 \× 22-22 x-60 x+x^{2}

21 \× 64-60 \× 22=85 x-82 x

1344-1320=3 x

24=3 x

x=8

mean proportional between 9 and 64

\ {9}/{x}=\ {x}/{64}

x^{2}=9 \× 64

x=3 \× 8

x=24

Go to Question:

Prev Question

Next Question