If Richard is getting a discount and his final price is $64 that means the answer must be above 64. That eliminates A, B, and C.
Use the formula: 20% of x = $64 and substitute the other two options. 20 percent of 84 is 16.8. 84-16.8=67.2 (not the correct answer). 20 percent of 80 is 16. 80-16=64(The Correct Answer).The answer must be $80 (D)
