We know that, Speed = DistanceTime
Speed of Hamid = 9 km1 h = 9 km/h
Speed of Akhtar = 12 km1 h = 12 km/h
Ratios are used to compare quantities which have same units. In this case, units of speed of Hamid and Akhtar is same i.e. km/h. Hence, we can find the required ratio.
∴ Ratio of speed of Hamid to the speed of Akhtar
= Speed of HamidSpeed of Akhtar
912 = 34 = 3:4 [Dividing numerator and denominator by HCF of 9 and 12 i.e. 3]