Question

By walking at 3/4 th of his usual speed, Ramu can reach his office 20 minutes later than usual. The time taken at usual speed is (in minutes)

Answer 1

Let the usual speed be x km/min
And the time taken at usual speed be y min
Then
3x/4*(y+20) = x*y( d = s*t and distance is same)
3y/4 + 15 = y
y - 3y/4 = 15
Y/4 = 15
Y = 60
60 min is the answer