Is 5 cups less than 40 fluid ounces?

Usually 5 cups is 40 fluid ounces. However, that needs to be qualified.

A British Imperial small cup = 227ml = 1/4 fifth = 1/2 pound water = 8 imperial fluid ounces = .96 US cups = 0.8 Imperial half pint cups = 0.908 metric equivalent cups (250 ml).

A US cup = 1.043 imperial small cups or 0.835 imperial large cups = 8 fl.oz. US = 8.344 imperial ounces = 236.8 ml = 0.9472 metric equiv.. cups

An imperial half pint cup = 1.25 small cups = 10 fluid ounces Imp. = 1.199 US cups = 283.7 ml = 1.135 metric equiv. cups

So with all these measurement possibilities, and their confusions, 5 imperial 1/2 pint cups(the largest cup) can be as much as 50 fluid ounces imperial (the smallest fluid ounce)or 5 imperial small cups(the smallest cup) can be as few as 38.34 fluid ounces US measure (the largest fluid ounce).

***To further confuse this, there are other measures which have been used over the years, and some presently, such as a teacupful (6 fl.oz.), a wineglassful (3 fl.oz.), a mugful or tankardful (10-12 fluid ounces) and the like.