Question

Kim uses decals to decorate 5 cars and 2 motorbikes. She uses 2/3 of the decals on the cars and 2/5 of the remaining on the motorbikes. She has 6 decals left. How many decals does Kim use on each car?

Answer 1

She uesed 1/3 * 2/5 of the total decal the second time, which is 2/15. So she used 2/15 + 2/3 = 12/15 of the decal. Which means what's left is 3/15 of the initial number, since its 6, the total number is 30. Which means she used 20 in the car, 4 in each, and 4 on the motorcycle, 2 in each.