Question

out of 1900 km, Vishal travelled some distance by bus and some by aeroplane.bus travel with average speed 60 km/ hr and the average speed of aeroplane is 700 km/hr.it take 5 hours to complete the journey.find the distance , Vishal travelled by bus

Answer 1

1900/5=(60t+700(5-t))/5
1900= -640t+3500
t=1600/640=2.5 h
t is time travel by bus
so distance travel by bus=60×2.5=150 km

Answer 2

$x + y = 5 \\ 60x + 700y = 1900 \\ \\ 60x + 60y = 300 \\ 60x + 700y = 1900 \\ - \: \: \: \: \: \ - \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: - \\ = - 640y = - 1 600 \\ y = 1600 \div 640 = 2.5 \\ x = 2.5 \\ y = 700 \times 2.5 = 1750km \: aeroplane \\ 150km \: bus$
150km bus se vishal travelled kiya