A box contains 9 green cubes, 8 green spheres, 9 blue cubes, and 10 blue spheres. What is the probability that an object chosen from the box at random is blue or a sphere? Please express your answer as a percent to the nearest percent.

Answer 1

number(blue OR sphere) = number(blue) + number(sphere) - number(blue AND sphere)
= 19 + 18 - 10 = 27

prob(stated event) = 27/36 = 3/4 = 75%