Answer:
2f + 10 = 20
Step-by-step explanation:
If he wants to give two candy bars to each friend, then each friend is worth 2f.
He wants to have 10 left over, so 10 + 2f must be equal to 20. In other words 2f = 20 - 10, which means 2f + 10 = 20.
I hope this makes sense.
