Simple Interest, Percent Change, Percent Error

Percent is based out of ______?

• 10

• 100

• 1000

• 400

The simple interest formula is I=Prt.  What does the t represent?

• Principle

• Interest

• Time

• Percent Rate

Starting money = $350.
Interest rate = 2.5%
TIme = 3 years.
How much interest?

• $7.50

• $26.25

• $87.5

• $262.50

Principal = $800
Interest Rate = 3.5%
Time = 6 months
Find the interest earned.

• 14

• 140

• 168

• 16.80

Sam borrowed $4,500 for 2 years and had to pay $630 simple interest at the end of that time. What rate of interest did he pay?

• 6%

• 7%

• 8%

• 9%

You lend $240 to your friend.  He pays you back $270.  What interest rate did you charge your friend?

• 88%

• 20%

• 12.5%

• 10%

Calculate the percent increase. Round to the nearest percent.

Original: 74

New: 85

• 0.15%

• 0.13%

• 13%

• 15%

Calculate the percent increase. Round to the nearest percent.

Original: 45

New: 92

• 51%

• 1.04%

• 104%

• .51

Lacey bought a new purse that originally cost $25 and is on sale for $15. Find the percent of change in the price in the purse.

• Decrease of 40%

• Decrease of 10%

• Decrease of 30%

• Decrease of 20%

Find the percent change.

Original amount: 72

New amount: 7

• 20% increase

• 90% increase

• 10% decrease

• 90% decrease