1/3 of Ali's stamps is equal to 2/3 of betty's stamps.If Ali has 85 stamps more than betty.How many stamps does Ali have?

I suggest solving this as a system of equations. Let x be the number of Ali's stamps and y be the number of Betty's.

x = y+85
x/3 = 2y/3

Now, you can set the x from the first equation in stead of the one in second:

(y+85)/3 = 2y/3
y+85 = 2y
y=85

Now that you know the number of stamps Betty has, you can find the number Ali has.