There were 8,000 people at a concert hall at first. 40% of the people at the concert were men and the rest were women. After some men and 50 women left, the ratio of the number of men to women who remained in the concert hall was 3 : 5. How many people left the concert hall?
+128472 8000 * .40 = 3200 were originally men
So
8000 - 3200 = 4800 were women
When 50 women left there were 4750
Let x be the number of men who left
And we ,now that
3200 - x 3
________ = ___ cross-multiply
4750 5
5 (3200 - x) = 3(4750)
16000 - 5x = 14250
16000 - 14250 = 5x
1750 = 5x
1750 / 5 = 350 men left
So 50 + 350 = 400 left
