72 is the correct answer I think
I think you meant the two <em>segments</em><em> </em>are identical, if so then:

The probability that all three are blue it's 3:14
To find the integer, you must cross multiply, group the same terms, then divide both side by 2:
Solution:
4/(x-3)= 2/3
12 = 2x-6
18=2x
x= 9
Since it says only write a expression, you can do 45xM= ?/?