Math, never has been my strong suit Help!!!!!!

Question

I am three years younger than my brother. And I am 2 years older than my sister. My moms age is one less of three times my brothers age. When you add all of our ages, you get 87. What are our ages?

Answer 1

Let x = my age

y = my brother's age

z = my sister's age

A = my mom's age

I am 3 years younger than my brother: x = y - 3

I am 2 years older than my sister: x = z + 2

My mom is 1 year less than 3 times my brother's age: A = 3y - 1

Our ages combined add up to 87: x + y + z + A = 87

We can make everyone's age related to my brother's age then solve for his age using the last equation. First, we need to get my sister's age in relation to my brother:

x = z + 2--->y - 3 = z + 2--->y - 3 - 2 = z--->z = y - 5

Now, use the last equation and substitute x, z and A in terms of y:

x + y + z + A = 87

(y-3) + y + (y - 5) + 3y - 1 = 87

6y - 9 = 87

6y = 87 + 9

6y = 96

y = 96/6

y = 16

Using this value for y we can now solve for all the other ages. I'll leave this up to you.

Hope this helps!