You may have multiplied the reciprocal of both numbers: $\displaystyle\frac{{8}}{{21}}\cdot\frac{{4}}{{3}}\usepackage{cmbright}\Huge\$ . To solve the problem, multiply the first number by the reciprocal of the second number: $\displaystyle{2}\frac{{5}}{{8}}\div\frac{{3}}{{4}}=\frac{{21}}{{8}}\cdot\frac{{4}}{{3}}\usepackage{cmbright}\Huge\$ . The correct answer is $\displaystyle{3}\frac{{1}}{{2}}\usepackage{cmbright}\Huge\$ .