Ratio and Proportion Practice Test 1

Question : 9 of 40

Marks: +1, -0

The ratio of three numbers is 7 : 8 : 9 and the sum of their squares is 4,850. Find the sum of the numbers.

Solution:

Let the numbers be 7x, 8x, 9x.
Then,

(7x)^2 + (8x)^2 + (9x)^2 = 4,850

49x^2 + 64x^2 + 81x^2 = 4,850

194x^2 = 4,850

x^2 = 25

x^2 = 5

∴ The numbers are 35, 40, 45.
So, their sum is 120

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