Train A takes 45 minutes more than train B to travel a distance of 450 km. Due to engine trouble speed of train B falls by a quarter, so it…

Let speed of A = A km/hr and speed of B = B km/hr

According to the question;

⇒ 450/A – 450/B = 45/60

⇒ (1/A – 1/B) = 1/600 ---- (1)

And

⇒ 450/(3B/4) – 450/A = 30/60

⇒ 4/3B – 1/A = 1/900 ---- (2)

Adding both the equations;

⇒ 4/3B – 1/B = 1/600 + 1/900

⇒ 1/3B = 5/1800

⇒ B = 120 km/hr

Putting this value in equation 1;

⇒ 1/A = 1/600 + 1/120 = 6/600

⇒ A = 100 km/hr

∴ Speed of A = 100 km/hr

Please explain briefly