Chapter 7 - Section 7.6 - Percent and Problem Solving: Interest - Exercise Set - Page 518: 9

700 dollars

I=PRT Let P=2500dollars , R=16% ,T = 21 months 21 months =$\frac{21}{12}$ year = $\frac{7}{4}$ I = 2500 $\times$16% $\times$ $\frac{7}{4}$ Write 16% as a decimal I = 2500$\times$0.16$\times$ $\frac{7}{4}$ Multiply I = 400$\times$$\frac{7}{4}$ =$\frac{2800}{4}$=700 The simple interest is 700 dollars.