Investment Interest and Equations

The video tutorial explains how Phyllis invested $8,000 at different interest rates and earned $430 in total interest after one year. It demonstrates how to set up and solve an equation to find out how much was invested at each rate. The process involves defining variables, formulating an equation, solving it, and verifying the solution using a calculator.

What is the total amount Phyllis invested?

• $4,000

• $8,000

• $6,000

• $10,000

What is the interest rate for the portion of the investment that earns less?

• 5%

• 6%

• 3%

• 4%

If X represents the amount invested at 6%, what expression represents the amount invested at 4%?

• 8,000 + X

• 8,000 - X

• X - 8,000

• X + 4,000

How is 6% expressed as a decimal?

• 6.0

• 0.006

• 0.06

• 0.6

What is the total interest earned from both investments after one year?

• $400

• $430

• $450

• $500

What is the equation used to model the total interest earned?

• 0.06X + 0.04(8,000 - X) = 430

• 0.06X + 0.04X = 430

• 0.06(8,000 - X) + 0.04X = 430

• 0.06X + 0.04(8,000 + X) = 430

What is the simplified equation after eliminating decimals?

• 6X + 4(8,000 + X) = 43,000

• 6X + 4(8,000 - X) = 43,000

• 6X + 4X = 43,000

• 6(8,000 - X) + 4X = 43,000

How much did Phyllis invest at 6%?

• $4,500

• $6,000

• $5,500

• $5,000

How much did Phyllis invest at 4%?

• $2,500

• $3,000

• $3,500

• $2,000

What is the purpose of checking the solution with a calculator?

• To calculate a different total

• To change the interest rates

• To verify the solution is correct

• To find a new solution