Applying proportional relationships to solve multi-step problems

How do you calculate the balance in an account, with interest?

• Subtract the interest from the principle amount
• Multiply the principle, rate and time
• Add the interest to the principle amount
• Add the principle amount and the time

Solution A is 30% acid and Solution B is 60% acid. How many gallons of each solution must be used to create a 60-gallon mixture that is 50% acid.

A school has a total of 3,300 students. The ratio of female to male students is 4 : 7. How many female students are there?

• 1,180

• 1,200

• 2,000

• 2,100

How much would a new car depreciate the first year if it costs:

$ 35,000

(New cars depreciate about 12% of their value each year)

• $4,000

• $4,200

• $30,800

• $39,200

Chris borrows $450 from Gavin. Gavin lets Chris choose either a simple interest loan for 10 years with a 3.5% interest rate or a loan compounded annually for 7 years with a 2% interest rate. Which should Chris choose if he wants the cheaper plan? Use I=P*r*t for simple interest (make sure to add I plus P at the end) and A=P*(1+r)^t for compound interest.

• The simple interest plan

• The compound interest plan

You put $300 in a savings account for one year. The bank pays interest of 7.5%. How much interest did you earn from the bank?

• $2.25

• $22.50

• $225

• $2250

Jerry borrowed $4,000 for 5 years at 6% simple interest rate. How much interest is that?

• $800
• $1,000
• $1,200
• $1,500

Karissa deposited $10,000 for 4 years at a rate of 6% interest. Find the amount Karissa has in her account after 4 years.

• $1,500

• $12,400

• $2,400

• $12,000

The population of a city of 450,000 increases 2.5% per year. Determine what the population of the city would be in 10 years.

• 4,190,951.59

• 4,190,952

• 576,038.04

• 576,038

To find simple interest, you do NOT need:

• Time

• Interest Rate

• Principle (amount of money you started with)

• Error