Gopal spent 3/5 of his money in the first week and 1/3 of the remainder in the second week. He spent $110 altogether. How much money did he have left?
Fraction spent in 1st week: , so fraction remaining after 1st week:
Fraction spent in 2nd week: , so fraction remaining after 2nd week:
With remaining in the end, it's obvious that
With $110 and being amount and fraction spent, respectively, and R and being amount and fraction remaining,
respectively, we get the following PROPORTION:
11R = 110(4) ------ Cross-multiplying
Amount remaining, or