Trina is purchasing a new bike. the store is having a 20% off sale, and she has a 10% coupon. the original price of the bike is $89.75. what is the final price?

We are given that:
i- The store is having 20% off sale
ii- Trina has a 10% coupon

Therefore, Trina will be having a discount = 20 + 10 = 30% of the bike's price
This means that:
Trina will pay 100% - 30% = 70% of the price

We are given that:
The original price of the bike = $89.75
We now know that:
Trina will pay 70% of its price

Therefore:
Final price = 70% * 89.75 = 0.7 * 89.75
Final price = $62.825

Hope this helps :)

Think of it as five or above give it a shove. change the 5 or above to the right to a zero and add one to the number on the left.