Lin's father is paying for a $20 meal. He has a 15%-off coupon for the meal. After the discount, a 7% sales tax is applied. How much is the discount?
The cost of the meal after the discount?
The final cost of the meal with taxes?

1) The 15%-off coupon is $3.

2) The cost of the meal after the discount is $17.

3) The final cost of the meal with taxes is $18.19.

Step:

1) To find the discount, try to find the amount of 1%, (20÷100 x 15 = 3)

2) To find the cost of the meal after discount (20-3 = 17)

3) To find the final cost, try find the taxes amount  (17÷100 x 7 + 17 = 18.19)

step-by-step explanation:

1. practice, practice & more practice

2. review errors

3. master the key concepts

do not try to memorise the processes.

4. understand your doubts.

5. create a distraction free study environment

6. create a mathematical dictionary

7. apply maths to real world problems.