Six. 2 1/3=7/3-> to get to have a denominator of 6 multiply by 2 to get 14/6
Then 1/2=3/6
14/6 + 3/6 = 17/6
17/6= 2 5/6
It would be 3/5 because if you simplify it you would bet 3/5
7n = n
If that is incorrect, then i am sorry
4 legged tables : x
3 legged stools : y
x + y = 20 y= 20 - x
4x + 3y = 68
Replace y by 20 - x so we only have one letter
4x + 3(20 - x) =68
4x + 60 - 3x =68
x + 60 = 68
x = 8
To find y replace x by 8
y = 20 - 8
y = 12
So you have 8 four legged chairs and 12 three legged stools.
Hope I helped!