Find the Original Numbers:

Two numbers are such that the ratio between them is 3:5. If each increased by 20, the ratio between the new numbers so formed is 7:9. Find the original numbers:

  1. 9, 15
  2. 24, 40
  3. 27, 45
  4. 15, 25
Anurag Mishra Professor Asked on 8th October 2015 in Maths.
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1 Answer(s)

Answer: (4) 15, 25

Explanation:-
Given-
The ration of two numbers = 3: 5
Then, the two numbers are 3 X and 5X

If each increased by 20,
Then, (3 X + 20)/(5 X + 20) = 7/9
by cross multiplication,
9 (3 X + 20) = 7 (5 X + 20)
27 X + 180 = 35 X + 140
35 X – 2 7 X  = 180 – 140
8 X = 40
X = 40/8
X = 5

Then, the original number 3 X = 3 x 5 = 15  &  5 X = 5 x 5 = 25

Hence, the answer is (4) 15, 25.

Anurag Mishra Professor Answered on 10th October 2015.
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