Question

The side of a square field ABCD is 90m. Its diagonal AC is north to south and corner B is to the west of D. Rohan and Rahul start walking from B and C in clockwise and anticlockwise directions respectively. Their speeds are 8 kmph and 10 kmph respectively. When will they cross each other second time?

• A. 30m from A on AD
• B. 10 m from B on BC
• C. 30 m from D on AD
• D. 10m from C on BC
• E. None of the above

Answer 1

The correct option is D 10m from C on BC

The following direction diagram has been used while solving the questions. Use this diagram as a reference.



Relative speed of Rahul and Rohan
$=(8+10)\times \frac{5}{18}=5mpersec$
Rohan and Rahul will cover 270 m is 54 sec
In 54 seconds Rohan will cover
$54\times \frac{20}{9}=120m$
It means first time they will cross at 30 m on AD from A.
In 72 seconds Rohan will cover
$72\times \frac{20}{9}=160m$
It means they will cross each other second time at 10 m from C on BC.