In a city, the water company increased the monthly water bill by $8\%$. The initial monthly cost is $\$54$. What is the cost after the increase?

A square garden has sides of $8\mathrm{ft}$. The gardener reduces each side by $1\mathrm{ft}$ to make space for a pathway. What is the percent decrease in the perimeter of the garden?

A pair of running shoes costs $\$80$. The store is offering a $25\%$ discount. Calculate the amount of discount and the sale price of the shoes.

A smartphone originally costs \$800. It is on sale for \$680. Calculate the percent discount.

A patient was prescribed a medication dose. It was increased by $15\%$ after $3$ days, and the new dosage is $23\mathrm{cc}$. What was the original dosage?

The student council borrowed $\$1,275$ from a local sponsor to organize a school event. The sponsor charges $6.5\%$ simple interest per year. How much interest will the student council owe after a year?

A community center paid $\$432$ in simple interest after $3$ years on borrowed funds for new equipment. The interest rate was $4.5\%$ per year. What was the original amount borrowed?

A $10$-year government bond paid $5.8\%$ simple interest per year. Over the $10$ years, the bond earned $\$4,640$ in interest. What was the principal of the bond?

Sofia plans to buy a car. Her loan statement indicates she will pay $\$1,350$ in interest for a $3$-year loan at $9\%$ simple interest per year. How much did Sofia borrow for the car?