Mark is 3 times as old as Sheri. In 5 years, the difference in their ages will be 24 years. How old are they now?

Question

Mark is 3 times as old as Sheri.  In 5 years, the difference in their ages will be 24 years.  How old are they now?

anonymous · Answer

So we need to write out a couple of equations to solve this.

Let M=Mark's age, and S=Sheri's age.

M=3(S)
(M+5) - (S+5) = 24

Do you understand how I got those equations?

anonymous · Answer

yes

anonymous · Answer

but I am still confuse how to get the answer

misty1212 · Answer

put the $3S$ for $M$ and solve $$3S+5-(S+5)=24$$

anonymous · Answer

That's fine, that was just the first step.

Now you have two equations, 
M=3(S)
(M+5) - (S+5) = 24
We can solve them.

You can substitute M = 3(S) into the other equation:
(3S + 5) - (S + 5) = 24
Now you just have to simplify that equation to find S

anonymous · Answer

s=12

anonymous · Answer

s=12 @livias.random

anonymous · Answer

Exactly. Now that you know what S is, substitute S = 12 into M = 3(S) and solve for M

anonymous · Answer

M=36

anonymous · Answer

Right, so now you have both ages :)