Making Maths Count
Maths Week Scotland 2019 – Stripes
Problem 6: Stripes
In Wuppertal Zoo, there is a tank containing 41 spectacular tiger fish. Each male fish has 111 stripes while each female has only 37 stripes. Unfortunately, the male fish caught a disease and two thirds of them died. How many stripes were on display in the tank after this?
Solutions to Problem 6:
Note that 111 is three times 37 so each male fish had three times as many stripes as a female fish. When two thirds of the male fish die, two thirds of the male stripes disappear. This gives the same number of stripes on male fish as we would have if all the male fish survived but had lost two thirds of their stripes and so had only 37 stripes instead of 111. So the number of stripes now on display is 41 X 37 = 1517