Question

A barrel contains 15 1/3 liters of water. 3/4 of the water was used to water plants.

Answer 1

Change the 15 1/3 to an improper fraction (46/3). Next multiply this by (3/4).
(46/3)(3/4) = 46/4 = 23/2 = 11.5 gallons was used to water the plants

15 1/3 - 11 1/2 = 46/3 - 23/2 = 92/6 - 69/6 = 23/6 = 3 5/6 gallons of water are left in the barrel