The only difference is: If you multiply or divide both sides of an equation by the same negative number, the equation remains the same, but If you multiply or divide both sides of an inequality by the same negative number, the inequality reverses.
40% of the beads were blue which means 60% of the beads were red. If all the blue beads were used that means 40% was used so you add the 25% of the red beads that were used which is why the answer is 65%.
