+0

help me solve this

+1
208
3
Ali and Bakar walked from A to B along the same route. Ali started his journey half an hour earlier than bakar .Bakar walked 6 km at an average speed of 4km/h for the whole journey. Both of them arrived at B at the same time. What was Ali's average speed
Guest May 24, 2017
Sort:

#1
+202
+2

examp. 12:00 start Ali                              Bakar:  4km ->1h

12:30 start Bakar                         6km->xh    <=> x=3/2h <=> x=90 min +12:30= 2:00

arrived at the same time so Ali arrived at 2 so he do:

6km->2h

ykm->1h <=>y=3km so 3km/h is the Ali's average speed!!!

I hope you understand!!!

Whitespy001  May 24, 2017
edited by Whitespy001  May 24, 2017
#2
+2

Average speed = Distance / Time

4= 6/ T, so T =6/4 =1.5 hours - that took Bakar to cover the 6 Km.

Ali's average speed = 6/ (1.5 + .5) =6 / 2 =3 Km/h - Ali's average speed.

Guest May 24, 2017
#3
+84171
+2

Bakar's Distance divided by his rate  = his total time   =  6km / [ 4km/h ]  =  3/2 hr

And Ali's Distance  divided by his unknown rate , R,  rate  = his total time  = 6km / [ R km / h ]

And Bakar's time  plus 1/2 hr   =   Ali's time .......so

(3 / 2)   + (1/ 2)  = 6 / R   simplify

[ 6 + 2] / 4=   6 / R

[ 8 / 4]   = 6 / R

2 = 6 / R     and we can write

1/2 =  R / 6    multiply both sides by 6

3  = R      and Ali's rate  = 3 km / hr

CPhill  May 24, 2017

39 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details