A round cake is shared between Abi, Elvira and Tina. The angle cut at the centre of the cake for each piece is that person’s age multiplied by 10. Abi 9 years old and Elvira is 14 years old. How old is Tina?

The cake is in the shape of a circle. How many degrees in a circle?

Abi is 9 years old so the angle of her slice is 9 x 10 = 90°, Elvera is 14 years old so her angle is 14 x 10 = 140°. Total angle used so far is 90° + 140° = 230°. The remaining angle belongs to Tina. 360° - 230° = 130°. Remember that the angle cut is Tina’s age multiplied by 10. (Tina’s Age x 10 = 130). We must divide 130 by 10 to give us Tina’s age. (130/10 = 13) Tina is 13 years old.