Posted by **Kate** on Tuesday, July 12, 2011 at 9:22pm.

Stacey buys a $1000 RRSP today. After one year she adds $2500. By the end of the second year, the money has grown to $3851 as it has earned interest over time. What rate of interest does the money earn?

1000x^2 + 2500x - 3851

Use the quadratic formula above and your calculator to solve for x and i.

There are two solutions to the quadratic equation. Which one would you choose? Why?

- Math -
**Max**, Tuesday, July 12, 2011 at 9:34pm
Choose the solution that makes sense. Most of the time only the positive solution makes sense.

- Math -
**Max**, Tuesday, July 12, 2011 at 9:42pm
Simple example:

I drop a ball from 16 feet up. Its height can be modeled as h = -16t^2 + 16, where h = height in feet and t = time in seconds. When will the ball hit the ground?

16t^2 - 16 = 0

t = -1, 1

It took -1 second? No way.

It took 1 second? Yes!

## Answer This Question

## Related Questions

- Math - Nico was stunned when he opened the mail. Here was a check for $322.50! ...
- math - Jeanette wishes to retire in 30 years at age 55 with retirement savings ...
- Mortgage Class - A borrower received a 30-year ARM mortgage loan for $120,000. ...
- Loans - A borrower received a 30-year ARM mortgage loan for $120,000. Rate caps...
- maths-- compound interest - find the compund interest on $2500 for one year at 4...
- math 117 - Kevin earned $165 interest for 1 year on an investment of $1500. At ...
- Finance - Your Uncle has two alternative inheritence for you. A. You receive ...
- Math(word problems) - 4.Tracie invested $x at 7% and $y at 6%. Write algebraic ...
- Math - Your Aunt will give your $1,ooo if you invest it for 10 years in an ...
- Finance - 2. You are now considering adding a corporate bond to your investment ...

More Related Questions