#### Answer

150 men and 450 women attended the concert.

#### Work Step by Step

Let X represent the number of men.
There are three times as many women as men.
Since the number of men is X, the number of women is three times the number of men, or 3 $\times$ X = 3X
A total of 600 people attended the concert, so we can set up the following equation:
X + 3X = 600
4X = 600
Divide both sides by 4
X = 150
Since X = 150, 3X = 450