Question

A box is filled with 11 blue cards, 2 green cards, and 7 brown cards. A card is chosen at random from the box. What is the probability that it is a blue or a brown card? Write your answer as a fraction in simplest form

Answer 1

11 blue
2 green
7 brown
total is 20 card
7 out of that 20 are brown
so x out of 100% are brown
7/20=x/100 - cross multiply
700=20x
x=700/20
x=70/2