Answer
$\frac{210}{150}$ = $\frac{7}{5}$
Work Step by Step
Americans spend time on working are 3 hours 30 minutes
Calculate time in minutes = 3 hr * 60 min + 30 min = 210 min
They spend time on household duties/caring for others are 2 hours 30 minutes
Calculate time spent in minutes = 2 * 60 + 30 min = 150 min
Americans spend time on working compared to household duties/caring for others = $\frac{210}{150}$ = $\frac{7}{5}$
