Answer:
(21 + 11)2 = 64
So, I don't think teachers do this, but this is my way of doing it
Okay, so first, I divided 64 by 2 :
64 ÷ 2 = 32
Then, I subtracted 11 from 32:
21
Now, to check, just do the problem :
(21 + 11)2 = 64
32 * 2 = 64
Marked down 15% means the new price would be 85% of the original price ( 100%-15% - 85%)
Multiply the original price by 85%:
5250 x 0.85 = 4462.50
The new price is $4,462.50