The sum of the squares of three numbers is 532 and the ratio of the first and the second as also of the second and the third is 3 : 2. The third number is -
A. 8
B. 12
C. 18
D. 20
Answer: Option A
Solution(By Examveda Team)
$$\eqalign{ & {\text{First}}:{\text{Second}} = 3:2, \cr & {\text{Second}}:{\text{Third}} = 3:2 \cr & = \left( {3 \times \frac{2}{3}} \right):\left( {2 \times \frac{2}{3}} \right) \cr & = 2:\frac{4}{3} \cr & \therefore {\text{Ratio between the numbers}} \cr & = 3:2:\frac{4}{3} \cr & = 9:6:4. \cr} $$Let the numbers be 9x, 6x and 4x
Then,
= (9x)2 + (6x)2 + (4x)2 = 532
⇒ 81x2 + 36x2 + 16x2 = 532
⇒ 133x2 = 532
⇒ x2 = 4
⇒ x = 2
So, third number = 4x = 4 × 2 = 8
Related Questions on Ratio
If a : b : c = 3 : 4 : 7, then the ratio (a + b + c) : c is equal to
A. 2 : 1
B. 14 : 3
C. 7 : 2
D. 1 : 2
If $$\frac{2}{3}$$ of A=75% of B = 0.6 of C, then A : B : C is
A. 2 : 3 : 3
B. 3 : 4 : 5
C. 4 : 5 : 6
D. 9 : 8 : 10
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