Question

Eight friends ate at a restaurant and agreed to share the bill equally. Because Judi forgot her money, each of her seven friends paid an extra $2.50 to cover her portion of the total bill. What was the total bill?

Answer 1

Judi's share was (7 x $2.50) = $17.50 .

That was really one share out of eight.
So the total bill was

(8 x $17.50) = $140.00 .