posted by norman on .
can anyone help with this?
suppose you bought some 32 cents stamps and some 20 cents stamps. you spent $3.92 for 16 stamps. how many of each stamp did you buy?
i got the equation--.32x + .20y = $3.92 but don't know how to solve for x and y
Step 1: Solve for y in equation (1).
.20y = 3.92 - .32x
Step 2: Substitute this value for y in equation (2). This will change equation (2) to an equation with just one variable, x.
.32x + .20(3.92 - .32x)= 3.92
multiply it out
.32x + (.20 x 3.92) - (.20 x .32x) = 3.92
solve for x, then go back and plug x into the equation and solve for y
yes now i understand the process. i just couldn't get past seeing x and y. thanks
.32x + .784 -.064x = 3.92
.256x + .784 = 3.92
.256x = 3.136
Hello Norman, in case u have not solved this yet, try this:
x+y = 16
32x + 20y = 392
You will get whole number answers for x and y.
If you do try hack revise your answer works if you do .32x6 is 1.92 and add .20x10 is 200 and add 1.92 and 2.00 you get 3.92