Question 1177099
Two kinds of fruits are displayed in a fruit stand. One is avocado fruit whose number is no more than thrice the other, which is melon. How many avocado and melons are there if there are atleast 20 total of fruits displayed

Let the number of melons be is x. 

According to the problem, the number of avocados is no more than thrice the number of melons. 

avocado ≤ 3 * melon

 at least 20 total fruits displayed. 

avocado + melon ≥ 20

melon ≥ avocado / 3 

Substituting this into the second equation

avocado + avocado/3 ≥ 20

Multiply by 3

3avocado + avocado ≥ 60

4avocado ≥ 60

avocado ≥ 15

avocado has to be a natural number and it is <= thrice the number of melons, the only sensible value for avocado is 15. 

We Know

avocado ≤ 3 * melon

15 ≤ 3 * melon

5 ≤ melon

 There are at least 5 melons .

So the possiblities 

- 15 avocados and 5 melons
- 12 avocados and 4 melons
- 9 avocados and 3 melons