Alana is having a party. she bought 3 rolls of streamers and 2 packages of balloons for $10.00. she realized she needed more supplies and went back to the store and bought 2 more rolls of streamers and 1 more package of balloons for $6.25. how much did each roll of streamers and each package of balloons cost?

Hello!

You can make two expressions based on what you know

let x represent the cost of balloons
let y represent the cost of streamers

2x + 3y = 10
x + 2y = 6.25

you can multiply the second equation by 2

2x + 4y = 12.50

You can subtract the two equations from each other to get y

-y = -2.50

Since y is negative we can multiply both sides by -1 to make y positive

y = 2.50

streamers cost 2.50 each

Now we plug this into one of the original equations to get the cost of balloons

x + 2(2.50) = 6.25

Multiply

x + 5 = 6.25

Subtract 5 from both sides

x = 1.25

The answers are
1 package of balloons cost $1.25
1 roll of streamers cost $2.50

Hope this helps!