Answer:
(3,2)
Step-by-step explanation:
Let's solve this via elimination method:

By subtracting equation 2 from equation one we obtain:

Next we can use any equation either 1 or 2 to determine what x is, I'll use equation 1. Let y=2 and so:

Therefore the solution for the system of equations is:
x=3 and y = 2 as an ordered pair we have (3,2)
Sarah is 14
The twins are 12
The youngest (n) is 7
14+(12+12)+7=45
n=7
Rectangle prisms have 6 flat surfaces.