Quantitative Aptitude - Arithmetic Ability Questions

4 hrs after a goods train passed a station, another train travelling at a speed of 72 km/hr following that goods train passed through that station. If after passing the station the train overtakes the goods train in 8 hours. What is the speed of the goods train?

What is the average of all natural numbers from 21 to 39?

What is the value of 36+729381+643

The average of 3 consecutive even numbers is A. If next 5 even numbers are added, then what is the average of these 8 numbers?

What is the value of (91 + 92 + 93 + ......... +140)?

If cosec2 θ = 625/576, then what is the value of [(sin θ – cos θ)/(sin θ + cos θ)]?

If √3 = 1.732, then the value of 9+233?

The least value of tan2x + cot2x is