There are some coloured rubber bands in a box. 3/8 of them are blue, 1/4 of them are re and 5/6 of the remainder are yellow. There are 20 yellow rubber bands. Find the total number of rubber bands in the box.
5/6 ths of (1 - 3/8 - 1/4) is to 20 as 1 is to x
5/6 ( 3/8) / 20 = 1/x
15 / 960 = 1/x
x = 64 in the box