SOLUTION: Steve and Robin have 16 cousins. Steve has 3 times as many as Robin. How many cousins does Steve have? I know the answer is 12 but how do I solve this so my son (and I) underst

Question 565319: Steve and Robin have 16 cousins. Steve has 3 times as many as Robin. How many cousins does Steve have?
I know the answer is 12 but how do I solve this so my son (and I) understand?
Sons 5th grade math is stumbling Dad!
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
let s = no. of Steve's cousins
let r = no. of Robin's cousins
:
Write a simple equation for each statement:
:
Steve and Robin have 16 cousins.
s + r = 16
:
Steve has 3 times as many as Robin.
s = 3r
:
In the 1st equation we can replace s with 3r
3r + r = 16
4r = 16
r = 16/4
r = 4 cousins for Robin
then we know s = 3r, therefore
s = 3*4
s = 12 cousins for Steve
:
Of course they should add up to 16 which they do

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