Let us assume that the amount Torin got from his grandparents = x
The amount Torin received from his cousin = y
Let us assume that the amount Torin got from his uncle = z
Now let us concentrate on the information's provided in the question.
Now
x = 50 + z
z = x - 50
z = y - 10
y = z + 10
We also know that
x + y + z = 135
Now if we replace the value of x and y that we have already got then
x + y + z = 135
50 + z +z + 10 + z = 135
3z + 60 = 135
3z = 135 - 60
3z = 75
z = 75/3
= 25
So the amount received from his cousin is $25
