An aeroplane travelled a distance of 400 km at an average speed of x km/hr. On the return journey … write down an equation in x and…
Answers:
(i) Time taken for the onward journey = 400/x hours.
(ii) Time taken for the return journey = 400/x + 40 hours.
According to the question,
⇒ 400/x + 40 = 400/x – ½
⇒ 800x = 800(x + 40) – x(x + 40)
⇒ x2 + 40x – 32000 = 0
⇒ (x + 200)(x – 160) = 0
⇒ x = – 200 (inadmissible) or 160
Hence, the required value of x is 160.