Answer:
Let x represent the number of letters sent to Europe and y represent the number of letters sent to the U.S.
$0.94 for each letter sent to Europe gives us the expression 0.94x.
$0.44 for each letters sent to the U.S. gives us the expression 0.44y.
Together the total was $3.70; this gives us the equation
0.94x+0.44y = 3.70
There were 5 total letters sent; this gives us the equation
x+y = 5
This gives us the system
0.94x + 0.44y = 3.70
x+y = 5
We will use substitution to solve this; we will isolate the variable x in the second equation. We can do this by subtracting y from each side:
x+y = 5
x+y-y = 5-y
x=5-y
Next we substitute this into the first equation:
0.94x+0.44y = 3.70
0.94(5-y)+0.44y = 3.70
Using the distributive property,
0.94(5)-0.94(y)+0.44y = 3.70
4.7-0.94y+0.44y = 3.70
Combining like terms,
4.7-0.5y = 3.70
Subtract 4.7 from each side:
4.7-0.5y-4.7 = 3.7-4.7
-0.5y = -1
Divide both sides by -0.5:
-0.5y/-0.5 = -1/-0.5
y = 2
There were 2 letters mailed to the U.S.
Substitute this into the second equation:
x+2 = 5
Subtract 2 from each side:
x+2-2 = 5-2
x = 3
There were 3 letters mailed to Europe.