A and b start from the same point and in the same direction at 7:00 am to walk around a rectangular field 400m x 300m. a and b walk at the rate of 3km/h and 2.5km/h respectively. how many times shall they cross each other, if they continue to walk till 12: 30 pm?
Answers
Total time for which A and B Travel = 5h 30 min = 5 1/2h (From 7:00am – 12:30 pm)
Speed of A = 3km/h
Therefore, Distance travelled by A in 5 1/2h
= 3 x 11/2 = 16.5km
And the speed of B = 2.5km/h
Therefore, Distance travelled by B in 5 1/2h = 2.5 x 11/2 = 13.75km
Therefore in 5 1/2h,
The difference in distance travelled by A and B is (16.5 - 13.75km.i.e...2.75km
The total extra distance needs to be travelled by one in order to cross the other by at least once.
= Length of path around the field
Perimeter of the rectangle =2(l+b)= 2(400+300) =1400m =1.4km
Hence A may cross more than once they may need at least 1.4x2 =2.8km
the difference between themselves but the difference is 2.75km, they can only once cross each other.
Step-by-step explanation:
Total time for which A and B Travel = 5h 30 min = 5 1/2h (From 7:00am – 12:30 pm)
Speed of A = 3km/h
Therefore, Distance travelled by A in 5 1/2h
= 3 x 11/2 = 16.5km
And the speed of B = 2.5km/h
Therefore, Distance travelled by B in 5 1/2h = 2.5 x 11/2 = 13.75km
Therefore in 5 1/2h,
The difference in distance travelled by A and B is (16.5 - 13.75km.i.e...2.75km
The total extra distance needs to be travelled by one in order to cross the other by at least once.
= Length of path around the field
Perimeter of the rectangle =2(l+b)= 2(400+300) =1400m =1.4km
Hence A may cross more than once they may need at least 1.4x2 =2.8km
the difference between themselves but the difference is 2.75km, they can only once cross each other.