Answer:
He will have 8 50-cent coins
Step-by-step explanation:
Let x = the number of 10-cent coins
Let y = the number of 50-cent coins
x + y = 20 y = 20 - x
[Set up an equation] .10x + .50y = 6.80
[Multiply both sides by 100] 10x + 50y = 680
[Plug-in] 10x + 50(20 - x) = 680
[Multiply] 10x + 1,000 - 50x = 680
[Combine like terms & subtract 1,000 from both sides] -40x = -320
[Divide both sides by -40] x = 8 coins
Have a nice day! - hopefully this is correct, I got a bit turned around for a bit lol
I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly. (ノ^∇^)
- Heather
