Carcass wrote:
In March 2010, my wife Sarmishtha was eight times as old as my daughter Surichi. In March 2020, she will be three times as old as my daughter. How old was my daughter in March 2010 ?
(A) 4 years
(B) 6 years
(C) 18 years
(D) 24 years
(E) 26 years
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITIONGRE - Math Book In March 2010, my wife Sarmishtha was eight times as old as my daughter Surichi.Let x = Surichi's age in 2010
So, 8x = Sarmishtha's age in 2010
This also means...
x + 10 = Surichi's age in 2020
8x + 10 = Sarmishtha's age in 2020
In March 2020, she will be three times as old as my daughter.We can write: (Sarmishtha's age in 2020) = 3(Surichi's age in 2020)
Substitute to get: 8x + 10 = 3(x + 10)
Expand: 8x + 10 = 3x + 30
Subtract 3x from both sides: 5x + 10 = 30
Subtract 10 from both sides: 5x = 20
Solve: x = 20/5 = 4
Answer: A