Question 38133
Let's call the length of AB, x.
Thus the length of BC is x - 1.
And the length of AC is x + (x - 1) - 10.
Now if we add all the sides we get 72...so
x + (x - 1) + (x + (x - 1) - 10) = 72 and
4x - 12 = 72
4x = 84
x = 21 and x - 1 = 20 is side BC
Choice A.