One third of a day = ___hrs

One-third of a certain journey was covered at the speed of 20km/hr ,one - fourth at 30km/hr and the rest at the speed of 50km/hr .find the average speed peer hour for the whole journey.

A car travels the first one third of a certain distant with a speed of 10 km/hr, the next one third distant with a speed of 20 km/hr and the last one third distance with a speed of 60 km/hr. The average speed of the car for the whole journey is 18 k m//h r b. 24 k m//h r c. 30 k m//h r d. 36 k m//h r

20 men complete one- third of a piece of work in 20 days. How many more men should be employed to finish the rest of the work in 25 more days? 10 b. 12 c. 15 d. 20

A car travels the first one-third of a certain distance with a speed of 10 km/hr, the next one-third distance with speed of 20 km/hr and the last one-third distance with a speed of 60 km/hr. The average speed of the car for the whole journey is