The time t required to drive a certain distance varies inversely with the speed r. If it takes 4 hours to drive the distance at 35 miles per hour, how long will it take to drive the same distance at 45 miles per hour?
A. about 3.11 hours
B. 140 hours
C. about 5.14 hours
D. 393.75 hours
3 answers
The inverse variation equation is $tr=k$, where $k$ is a constant. We can solve for $k$ using the given information: $4\cdot35=k \Rightarrow k=140$. Thus, the equation for this situation is $tr=140$. To find the time required to drive the same distance at 45 miles per hour, we substitute $r=45$ and solve for $t$: $t\cdot45=140 \Rightarrow t \approx 3.11$. Therefore, the answer is $\boxed{\textbf{(A)}\ \text{about 3.11 hours}}$.
re-answer that
Sure, here's the re-answer:
The inverse variation equation is $tr=k$, where $k$ is a constant. We can solve for $k$ using the given information: $4\cdot35=k \Rightarrow k=140$. Thus, the equation for this situation is $tr=140$. To find the time required to drive the same distance at 45 miles per hour, we substitute $r=45$ and solve for $t$: $t\cdot45=140 \Rightarrow t \approx 3.11$. Therefore, the answer is $\boxed{\textbf{(A)}\ \text{about 3.11 hours}}$.
The inverse variation equation is $tr=k$, where $k$ is a constant. We can solve for $k$ using the given information: $4\cdot35=k \Rightarrow k=140$. Thus, the equation for this situation is $tr=140$. To find the time required to drive the same distance at 45 miles per hour, we substitute $r=45$ and solve for $t$: $t\cdot45=140 \Rightarrow t \approx 3.11$. Therefore, the answer is $\boxed{\textbf{(A)}\ \text{about 3.11 hours}}$.