Ratio and Proportion Practice Test 4

Question : 19 of 40

Marks: +1, -0

The ratio between two numbers is 4 : 5. If each number is increased by 8, the 40 : 49. Find the difference between the squares of these numbers.

2,900
2,916
2,280
2,180
2,282

Validate

Solution:

Let the numbers be 4x and 5x.Then,

{4x+8}/{5x+8}=40/49

49(4x + 8) = 40(5x + 8)
196x + 392 = 200x + 320
4x = 72
x = 18
∴ Numbers are 4x = 4 × 18 = 72
5x = 5 × 18 = 90
Hence, difference of their squares = 8,100 – 5,184 = 2,916

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