Question

Two boats start together and race across a 62-km-wide lake and back. Boat A goes across at 62 km/h and returns at 62 km/h. Boat B goes across at 31 km/h, and its crew, realizing how far behind it is getting, returns at 93 km/h. Turnaround times are negligible, and the boat that completes the round trip first wins. (a) Which boat wins

Answer 1

Answer:

boat A

Explanation:

Distance to one point of the race = 62 km

Speed of boat A across the distance = 62 km/h

Speed of boat A to return the same distance = 62 km/h

Time = Distance / Speed

Time taken by boat A to cover the first length

$\text{Time}=\frac{62}{62}=1\ hour$

Time taken by boat A to cover the return length

$\text{Time}=\frac{62}{62}=1\ hour$

So, total time taken by boat A is 1+1 = 2 hours

Speed of boat B across the distance = 31 km/h

Speed of boat B to return the same distance = 93 km/h

Time = Distance / Speed

Time taken by boat A to cover the first length

$\text{Time}=\frac{62}{31}=2\ hour$

Time taken by boat A to cover the return length

$\text{Time}=\frac{62}{93}=0.67\ hour$

So, total time taken by boat B is 2+0.67 = 2.67 hours

Hence boat A wins.