The Total solution for NCERT class 6-12
⇒ (x + 5)(360-1/x) = 360
⇒ 360 – x + 1800-5/x = 360
⇒ x2 + 5x + 10x –1800 = 0
⇒ x(x + 45) -40(x + 45) = 0
⇒ (x + 45)(x – 40) = 0
⇒ x = 40, -45
As we know, the value of speed cannot benegative.
Therefore, the speed of train is 40 km/h.