CTET 2 Math and Science Jul 2019 Paper

Question : 34 of 120

Marks: +1, -0

If x is added to each of 14, 12, 34 and 30, the numbers so obtained, in this order, are in proportion. What is the value of

√{12x+9}

Solution:

(14 + x) : (12 + x) :: (34 + x) : (30 + x)
(14 + x) (30 + x) = (12 + x) (34 + x)

420 + 44x + x^2

= 408 + 46x + x^2

2x = 12

x = 6

∴ Value of

√{12x+ 9}

=√{12×6+9}

=√{72+9}=9

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