SAT Mathematics Practice Test 2

There are 60 minutes in each hour, and so there are $60\mathit{h}$ minutes in h hours. Since h hours and 30 minutes is equal to 450 minutes, it follows that $60\mathit{h}+30=450$. This equation can be simplified to $60\mathit{h}=420$, and so the value of h is $\frac{420}{60}=7$