Arithmetic-22 (CAT-2004)

Two boats travelling at 5 and 10 km per hour, head directly towards each other. They begin at a distance of 20 km from each other. How far apart are they (in kms) one minute before they collide?

(1)1/12                       (2)1/6             (3)1/4             (4)1/3

Solution follows here:

Solution:

Do not waste time and energy here with the redundant data. “How far apart are they (in kms) one minute before they collide”, to find this, the speeds of the boats are enough. Two boats travelling at 5 and 10 km per hour, head directly towards each other, in one minute they travel 5*(1/60) + 10*(1/60) = 15/60 = ¼ km. Therefore, one minute before they collide, they would be ¼ km apart.

The formula used is “distance in km = (speed in kmph)*(time in hours)”

Answer (3)