1. 1. Warmups 2. Check HW Find (a) the simple interest and (b) the amount paid for the loan. 1.$12,000 borrowed at 4.9% for 4 years. 2.$18,500 borrowed at 19.9% for 180 months.

2. 4.4 Continued: Working backwards to find r or t in I=Prt

3. Find the interest rate How to: Normally in I =Prt, we multiply to find the interest. So, when working backwards, we divide. Example 1: Find the simple interest rate if I=$116.25, P=$1550, and t=9 months.

4. Find the time. Divide! Example 2: Find the time if the interest earned is $45.60, the principal is $2400, and the interest rate is 3.8%.

5. Try it yourself (from page 182)