If John is 12 and Sarah is 9, what is the radius of their money if their dad gave them €75 based on their ages?

So The ratio of their ages would be 12:9 and so see how much money they would get I’m going to put that into an equation.

Since in total their ages add up to being given a total of €75, my equation will be 12x+9x=75.

Now to solve, 21x=75
x=4 11/21, since the equation asked for ratio we can round.

12(4 11/21):9(4 11/21)

Or you could do the easier method of just looking at fractions.

So their ages add up to 21, for John, 12:21 is equal to 4:7 and Sarah is 3:7.

4/7= x/75
x= about 42.8

For Sarah 3/7=x/75
x=about 32.2

So John will have €42.8 and Sarah will have €32.2.
***Both ways work but the second one is faster

Hope this helps!