Answer:
In x - 5 years.
Step-by-step explanation:
5 years ago:
Sam's age: x
Nina's age: 2x
Now:
Sam's age: x + 5
Nina's age: 2x + 5
Let t be the number of years from now that Nina will be 1.5 times Sam's age.
In t years:
Sam's age: x + t + 5
Nina's age: 2x + t + 5
Nina will be 1.5 times Sam's age:
2x + t + 5 = 1.5(x + t + 5)
2x + t + 5 = (3/2)(x + t + 5)
2(2x + t + 5) = 3(x + t + 5)
4x + 2t + 10 = 3x + 3t + 15
4x + 10 = 3x + t + 15
x - 5 = t
t = x - 5