The question is not written well.
More like this:
Bob, Ali, and Glen went shopping. The combined bill for all of them was $780. If Ali and Glen spent the same amount, and Bob spent as much as both Ali and Glen, then how much did each person spend?
SPENT
Bob x+x
Ali x
Glen x
TOTAL $780
Bob spent 390 dollars.
Ali spent 195 dollars.
Glen spent 195 dollars.