The duration of a railway journey varies as the distance and inversely as the velocity; the velocity varies directly as the square root of the quantity of coal used, and inversely as the number carriages in the train. in a journey of 50 km in half an hour with 18 carriages, 100 kg of coal is required. how much coal will be consumed in a journey of 42 km in 28 minutes with 16 carriages.
Answers
Given:
The duration of a railway journey varies proportionally to the distance.
The duration of a railway journey varies inversely as the velocity.
The velocity varies directly as the √coal used.
The velocity varies inversely as the number carriages.
Distance = 50 km
Time = 30 min
Carriages = 28
Coal = 100 kg
To find:
The coal required for a journey of 42 km in 28 minutes with 16 carriages.
Solution:
Calculate velocity for 50 km,
Velocity = Distance / time
50/30
Original velocity = 5/3
Calculate velocity for 42 km,
42/28
New veolocity = 3/2
Hence, the amount of coal needed will be 100/81.
Calculate the amount of coal per km for 50 km train,
2 kg of coal per km
Substituting and solving using ratios,
2 / coal required = 100 / 81
162 = 100 * coal required
Therefore,
Coal required = 1.6 kg / km
Hence for 42 km,
We get,
42 * 1.6 = 67.2 kg
Therefore, 67.2 kg of coal will be consumed in a journey of 42 km in 28 minutes with 16 carriages.
Answer:
64kg
Explanation:
just correct answer