37 trees are planted in a straight line such that distance between any two consecutive trees is same. A car takes 20 seconds to reach the 13th tree. How much more time (in seconds) will it take to reach the last tree?

Let the distance between any two consecutive trees = $$d$$ metres

=> Total distance between the 37 trees = $$36d$$ metres

Time taken to reach the 13th tree = 20 seconds

=> Speed of car = distance/time

= $$\frac{12d}{20}=\frac{3d}{5}$$ m/s

Thus, time taken to reach the last tree from the first tree = $$\frac{36d}{\frac{3d}{5}}$$

= $$36\times\frac{5}{3}=60$$ seconds

$$\therefore$$ The car will take (60-20) = 40 seconds more to reach the last tree

=> Ans - (B)