Subject: General Aptitude · Chapter: Time and Distance · Exam: 2009 · Marks: · Difficulty:
Two cars $X$ and $Y$ start from places $A$ and $B$ respectively which are 700 km apart at 9 a.m. Both the cars run at an average speed of 60 km/hr. Car X stops at 10 a.m. and again starts at 11 a.m. while the other car continues to run without stopping. The two cars cross each other at
(a)2 : 40 p.m
(b)3 : 20 p.m
(c)4 : 10 p.m
(d)4 : 20 p.m
Answer
Answer (as printed): B
Explanation
Suppose they meet x hrs after 9 a.m. Then, Distance travelled by car X in (x – 1) hrs + Distance trav- elled by car Y in x hrs = 700 km ⇒ 60(x – 1) + 60x = 700 ⇒ 120x = 760 760 19 ⇒x= = hrs = 6 hr 20 min. 120 3 So, they cross each other 6 hr 20 min after 9 a.m. i.e., at 3 : 20 p.m.
Explanation as extracted from the printed page; notation may be imperfect.