Imagine having 20 currency notes, consisting of $5 bills, and $10 bills that total $125. Write a system of equations to describe the situation.

Hi,

Reading the problem you can understand that you have 20 currency notes. So, all the currency notes (5 and 10) summed are 20.

Now, you know that there are some 5 and 10 bills of these, but you don't know how many of these are $5 or $10 ... you only know that summing all these bills give $125.

Setting a sistem of linear equation would be like this:

i call x the $5 bills and y the $10 bills.

x+y = 20

5x + 10y = 125

The final results are x = 15 and y = 5

Hope it is clear!

X-the $5 bills

y-the $10 bills

x+y=20

5x+10y=120

It's a system.