An aeroplane flies twice as fast as a train which covers 60 miles in 80 minutes. What distance will the aeroplane cover in 20 minutes ?

Time taken to cover 60 miles = 80 min = $$\frac{4}{3}$$ hrs
∴ Speed of the train = $$\left( {60 \times \frac{3}{4}} \right)$$  mph = 45 mph
Speed of the aeroplane = (2 × 45) mph = 90 mph
Distance covered by the aeroplane in 60 min = 90 miles
Distance covered by the aeroplane in 20 min :
= $$\left( {\frac{90}{60} \times 20} \right)$$  miles
= 30 miles