The average age of Ruby and Soni is 40 years. The ratio of their ages is 11 : 5 , respectively. What the age (in year) of Soni?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 25.
Let Ruby's age be R and Soni's age be S.
So, (R + S)/2 = 40
⇒ R + S = 80 .....(1)
Also, R/S = 11/5
⇒ R = (11/5)S
Substitute R = (11/5)S into equation (1),
(11/5)S + S = 80
⇒ (16/5)S = 80
⇒ S = 80(5/16) = 25
Therefore, Soni's age is 25 years.