direct and inverse proportion

1-A truck covers a distance of 510 km in 34 litres of diesel. How much distance would it cover in 20 litres of diesel. 

2- A taxi charges a fare of Rs 2550 for a journey of 150 km. How much  would it charge for a journey of 124 km.

1- If 35 men can reap a field in 8 days, in how many days can 20 men reap the same field?

2- If 12 men can dig a pond in 8 days. How many men can dig it in 6 days?