In order to determine the amount of money Rain, Kevin and Eric have, write the given situation as an algebraic equation.
If x is the money of Raina, y the money of Kevin and z the money of Eric, you have, based on the given problem, the following equations:
x + y + z = 66 All of them have a total of $66
y = 3z Kevin has 3 times what Eric has
x = z - 9 Raina has $9 less than Eric
Replace the expressions for x and y into the first equation and solve for z, as follow:
(z - 9) + (3z) + z = 66
z - 9 + 3z + z = 66
3z = 66 + 9
3z = 75
z = 75/3
z = 25
Next, replace the previous value of z into the expressions for x and y:
y = 3(25)
y = 75
x = 25 - 9
x = 16
Hence, the amount of money each of them has is:
Raina: $16
Kevin: $75
Eric: $75
