Writing Percent Equations

A cell phone company dropped the prices on their phones by 7%. Which equation shows the relationship between the p, the old price of the phones, and n, the new price of the phones?

• p= 0.07n

• p = n - 1.07

• p = n - 0.07

• p = n - 0.07n

Sam drew a square with each side being exactly 12 centimeters long. If he wanted to make the square 12% larger which expression can he use to find the new sides length?

• 12 x 0.12

• 12+ 1.12

• 12 x 1.12

• 12 + 0.12

Each new rectangle is 21% longer than the original. Write an equation to represent the relationship between the length of an original rectangle, b, and the length of the new rectangle, c.

• c = 1.21b

• c = 1b + 0.21b

• c = (1+0.21)b

• All of the above

Which story matches with the equation c = 1.25b?

• Did you know that if you do not cut hair, it can grow 25% longer in a month?

• My friend always eats 20% of whatever I bring for lunch.

• My phone bill costs 25% less this month than last month.

• A candy bar is now 50% longer than it originally was.

Which story matches with the equation c = 0.80b?

• Did you know that if you do not cut hair, it can grow 25% longer in a month?

• My friend always eats 20% of whatever I bring for lunch.

• My phone bill costs 25% less this month than last month.

• A candy bar is now 50% longer than it originally was.

Which story matches with the equation c = 1.50b?

• Did you know that if you do not cut hair, it can grow 25% longer in a month?

• My friend always eats 20% of whatever I bring for lunch.

• My phone bill costs 25% less this month than last month.

• A candy bar is now 50% longer than it originally was.

Write a story for the following equation: c = 0.75b

Jayla's bank account increased by 7% this year. Write an equation to represent the relationship between the amount that Jayla started with, b, and the amount she has now, c.

Do you have any questions on writing equations for percent problems? If so, type them below.