7 type A shoes, since they only take one hour
4 x 7 = 28
7 x 10 = 70
70 - 28 = 42 (it gives a 42 dollar profit)
Even if type B can give you more money after sold, you don't have enough time to even complete 1 shoe, which means -5 dollars for him, because it takes 12 1/2 hours to complete one shoe
hope this helps