In a container, there were a total of 450 white and black beads. 40% of them are white beads. Angus took out some white beads. As a result, the remaining white beads made up 25% of the beads left in the container. How many white beads did Angus take out?

white beads

The number of white beads: 450 × 40% = 180

The number of black beads: 450 – 180 = 270

After some red beads were taken out, the percent for black beads: 100% – 25% = 75%

Then, use the formula: whole = part ÷ percent

The total left beads: 270 ÷ 75% = 360

Thus, the white beads taken out: 450 – 360 = 90