He would pay $320 at a discount of 20%. The first step in solving this is hidden in the sentence “discount of 5%, he would pay $20 less”. This informs us that 5% of the price and $20 are the same Our next step is to find how much 100% of the price is Multiplying 5 and 20 gets us 100, so multiplying 5% by 20 will get us 100% We already know that 5% is $20, so we can multiply $20 by 20 to get to 100% percent of the price (20*20=400) Now that we know the total price, we can find a discount of any percent. Since we know that a five percent discount will give you $20 dollars off, we can deduce that a 20% discount will give us $80 off. (20/5=4) (4*20=80) (400-80=320!) Hopefully this helps, if you need me to explain anything again I’ll try my best!