E 4/7 of the seafood in a fridge was prawns and the rest was crayfish. After Mr Kang
cooked an equal mass of prawns and crayfish, there was 3/4kg more crayfish than
prowns left.
Find the mass of the prawns at first.

Acompany produces packets of soap powder labeled “giant size 32 ounces.” the actual weight of soap powder in such a box has a normal distribution with a mean of 33 oz and a standard deviation of 0.7 oz. to avoid having dissatisfied customers, the company says a box of soap is considered underweight if it weighs less than 32 oz. to avoid losing money, it labels the top 5% (the heaviest 5%) overweight. how heavy does a box have to be for it to be labeled overweight?