Question

The average weight of a watermelon is 4.61 kg. The average weight of a coconut is 2.22 kg less than a watermelon. The total weight of an equal number of coconuts and watermelons is 140 kg. How many coconuts are there? ​

Answer 1

Since the average weight of a coconut is 2.22 kg less than a watermelon, its average weight is

`4.61-2.22=2.39`Let n be the number of coconuts and watermelons. The total weight of n coconuts and n watermelons is

`4.61n+2.39n = 7n`

If we want this total to be 140, we have

`7n=140 \iff n=(140)/(7)=20`

So, you have 20 coconuts and 20 watermelons.