Question

If 36 :27 ::12 :?
This is questions from Ntse Std 10 Mental Ability Test Paper.....If Anyone know answer pls help......

Answer 1

If four quantities a,b,c and d are such that the ratio a : b is equal to the ratio c : d then we say a,b,c and d are in proportion or a,b,c and d are proportional.

We express it by writing a : b :: c : d .

$\boxed { \pink { If \:a:b::c:d \implies ad = bc }}$

$Here, a = 36, b = 27, c = 12 \: d = ?$

$\implies ad = bc$

$\implies 36 \times d = 27 \times 12$

$\implies d = \frac{27 \times 12}{36}$

$\implies d = 9$

Therefore.,

$\red { Required \: number } \green {= 9 }$

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