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
