Answer:
150 men and 252 women
Explanation:
Ratio:
Men : Women = 5 : 9
Number of men = 5x
Number of women = 9x
42 women left the museum.
Number of remaining women = 9x - 42
New ratio = 2 : 3

3*5x = 2*(9x - 42)
15x = 2*9x - 2*42
15x = 18x - 84
18x - 84 = 15x
Add 84 to both the sides,
18x = 15x + 84
Subtract 15x from both sides,
18x - 15x = 84
3x = 84
Divide both sides by 3,
x = 84 ÷ 3
x = 28
Number of men = 5 * 28 = 140
Number of women = 9*28 = 252