A bag contains white marbles and red marbles, 90 in total. The number of white marbles is 6 less than 5 times the number of red marbles. How many white marbles are there?

W = 72

Step by step explanation:

White = W

Red = R

W + R = 90

Write an equation

W = 5R - 6

Substitute

5R - 6 = 90

Add 6 to both sides of the equation

5R = 90

Simplify

90 : 5 = 18

R = 18

90 - 18 = W

W = 72

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