Pooja drives to work every weekday morning, departing at 8:30 am and arriving exactly on time at her usual speed of 48 km/h. When she drives at 40 km/h instead, she is 6 minutes late. One morning, she covers two-thirds of the route in one-third of her usual total commute time, and then stops for 4 minutes. The speed, in km/h, at which she should drive the remaining distance to arrive exactly on time is:
let her time be "t" minutes. d=s*t == 48*t =40(t+6) t= 30 minutes
d=24km 2/3 d = 16 km "d " remaining is 8km 2/3 d is covered in 1/3 time = 10 minutes + 4 minutes stop = 16 minutes remaining. now, 8 km in 16 minutes = @30km/h