A family, planning a weekend trip, decides to spend not more than a total of 8 hours driving. By leaving… · ABC26GN3671
Subject: General Aptitude · Chapter: Time and Distance · Exam: Campus Recruitment 2010
A family, planning a weekend trip, decides to spend not more than a total of 8 hours driving. By leaving early in the morning, they can average 40 miles per hour on the way to their destination. Due to the heavy Sunday traffic, they average only 30 miles per hour on the return trip. What is the farthest distance from home they can plan to go?
(a)120 miles or less
(b)Between 120 and 140 miles
(c)140 miles
(d)Between 140 and 160 miles
(e)160 miles or more
Answer
Answer (as printed): B
Explanation
Ratio of speeds while going and returning $=40: 30=4: 3$. Ratio of times taken while going and returning $=3: 4$. Time taken while going $=\left(\frac{3}{7} \times 8\right) \mathrm{hr}=\frac{24}{7} \mathrm{hr}$. Time taken while returning $=\left(\frac{4}{7} \times 8\right) \mathrm{hr}=\frac{32}{7} \mathrm{hr}$. $$\begin{aligned} \therefore \text { Required distance } & =\left(40 \times \frac{24}{7}\right) \text { miles }=\frac{960}{7} \text { miles } \\ & =137.14 \text { miles. } \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.