A boy starts from his home at a certain time with certain speed to pickup his girlfriend from office at 4:00 pm. One day his girlfriend left the office at 2:00 pm and starts walking to home with a speed of 30 km/hr and meets the boy on the way who left his home at his usual time they reached home 40 min earlier then their usual time. Find the speed of boy?
Answers
Answer:
150 km/Hr
Step-by-step explanation:
Total Time Saved = 40 min
This has the time to reach to office and coming back to that point where they meet
Hence time taken by boy from that point to office = 40/2 = 20 Min = 1/3 hr
Hence they meet 20 mins before 4 :00 PM = 3: 40 PM
Girl walked for 1 hr 40 min = 5/3 hr
Speed of girl = 30 km/hr
Distance covered by girl = 30 * 5/3 = 50 km
Time taken by boy to cover 50 km = 1/3 hr
Speed of Boy = 50/(1/3) = 150 km/Hr
Answer:
Step-by-step explanation:
1. We have 4 points A is home point, D is office point, C is point where girl is standing when boy leaves and B is point of meeting.
2. Girl leaves at 2 pm at 30 kmph and boy leaves at 4 pm. By the time boy leaves girl already have covered 30 kmph * 2 hrs = 60 km
3. They reaches 40 minutes before means boy did not go from point B to D which takes 20 minutes per side as per the calculation. Here relative time is 2 hrs out of which 20 minutes belongs to boy which means 100 minutes belongs to woman. Ratio of time (M:W)= 1:5 then ratio of speed will be (5:1). Here 1 belongs to the speed of women I.e. 30 kmph and then 5 will be 5*30=150 kmph.
Hence speed of boy is 150 kmph
