Mary is 5 times the age of her son Brian. In 6 years she will be 3 times his age. How old are they both now?

Question

this question was from 8th grade algebre 1 class                                                                                                

Answer 1

Here's what we know

m = 5b

m + 6 = 3(b + 6)

 

We have a value for m, so let's plug that in:

5b + 6 = 3(b + 6)

Distribute:

5b + 6 = 3b + 18

Subtract 3b:

2b + 6 = 18

subtract 6:

2b = 12

Divide by 2:

b = 6

 

Now we solve for m:

m = 5 * 6

m = 30

 

Check our answers:

30 + 6 = 3 * 6 + 18

36 = 18 + 18

36 = 36