Question

Q1) A man traverses a street in 6 minutes , walking at a speed of 4km/h . Find the lenght of the street .

Q2) Rima goes on a trip to a town 120km away from her home . She travels a distance of 80 km by taxi and the remaining distance by bus . If both the taxi and the bus run at a speed of 60km/h , find the total time taken by Rima to reach the town .

Q3) A 256 m long train crosses a tree in 8 seconds . How long will it take to cross a 160 m long bridge ?

Answer 1

(1). 6min=6/60=1/10 second
SO THE LENGTH=4×1/10=2/5==0.4km=400meter or 40000 centimetres

(2)WE KNOW THE BOTH SPEED ARE SAME = 60KM/H
THEN,
TIME TAKEN BY THE TAXI =80/60HOUR
AND AND TIME TAKEN BY THE BUS =(120-80)/60 HOUR.
SO, THE TOTAL TIME = TIME TAKEN BY THE TAXI +TIME TAKEN BY THE BUS
=>80/60 + 40/60=12/6=2 HOURS

(3). distance = speed × time 
256m = speed ×8 
speed =256/8 
speed = 32m/sec. 
time taken to cross a 160m long = 
256+160=416 
time = 416/32 
=13 seconds

hope its help you dear:-)

Answer 2

1. speed =dist/Time
dist=time×speed
speed = 4km/hr=20/18m/sec
time =6min
dist=20/18×6=6.666...