There is fish in a tank problem...

Question

There are 31 fish in a tank. The fish are either orange x or red y. There are 7 more orange x fish than the number of red fish y. How many fish are orange x? How many fish are red y?

Answer 1

x = y+7

x+y = 31

y+7 + y = 31

2y + 7 = 31

2y = 24

y = 12

12 red fish

19 orange fish