Since the ratio is a part to part ratio (5 to 3) just change it to a part to whole ratio, 5 hot drinks to 8 drinks total to make things easier first. Than divide 400 by 8 to see the scale factor which is 50. Finally multiply 5 times 50 to find out how much hot drinks there was total which is 250. Ever seen this before: 5 hot drinks : 8 total drinks x50 = x50 = 250 hot drinks : 400 total drinks
