Home » Aptitude » Ratio, Proportion » Question
  1. Two numbers are in the ratio 7 : 11. If 7 is added to each of the numbers, the ratio becomes
    2 : 3. The smaller number is
    1. 39
    2. 49
    3. 66
    4. 77
Correct Option: B

Let the numbers be 7x and 11x respectively.

∴ 
7x + 7
=
2
11x + 73

∴  22x + 14 = 21x + 21
⇒  x = 7
∴  Smaller number
= 7x = 7 × 7 = 49
Second Method :
Here, a = 7, b = 11, x = 7, c= 2, d = 3
1st Number=
xa(c − d)
ad − bc

=
7 × 7(2 − 3)
7 × 3 − 11 × 2

=
49 × −1
= 49
21 − 22

2nd Number =
xb(c − d)
ad − bc

=
7 × 11(2 − 3)
7 × 3 − 11 × 2

=
77 × −1
= 77
21 − 22

∴  Smallest number = 49



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