The ratio of the present age of two girls is 3 : 4. After two year the ratio will be 7 : 9. Which of the following statement(s) is/are correct ?
I. Ratio of their ages after 10 year is 6 : 7.
II. Ratio of their ages after 12 year is 6 : 7.
Answer & explanation
Correct answer: option 1
I : II
Present ages 3 : 4
After 2 years, 7 : 9
_______________________
+2 +2
⇒ $\frac{3R+2}{4R+2} = \frac{7}{9}$
Using cross - multiplication method,
28R - 27R = (9 x 2) - (7 x 2)
⇒ R = 4
Present ages = 12, 16
Ratio of ages after 10 years = 22 : 26 = 11 : 13
12 years = 24 : 28 = 6 : 7
Therefore, only II statement is correct