Math
posted by Kate on .
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?

Choose the solution that makes sense. Most of the time only the positive solution makes sense.

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!