Math word problem

Question

Mike has 640 red and blue marbles. if he has three times as many red marbles as blue marbles, how many red marbles does he have?

Answer 1

Let x be the number of blue marbles.

Since he has three times as many red marbles as blue marbles, the number of red marbles is 3x

The total number of marbles is 640

So the number of blue marbles (x) + the number of red marbles (3x) = 640

solving for x: x + 3x = 640

4x = 640

x=160

The number of blue marbles (x) = 160.

He has three times as many red marbles as blue marbles, so the number of red marbles = 3 * 160 = 480