i travel the first part of my journey at 40 kmph and the second part at 60 kmph and cover the total distance of 240 km to my destination in 5 hours . how long did the first part of my journey last
the total time of journey = 5 hours . let ' x ' hours be the time that i travelled at 40 kmph therefore , 5 – x hours would be time that i travelled at 60 kmph . hence , i would have covered x × 40 + ( 5 − x ) 60 kms in the 5 hours = 240 kms . solving , for x in the equation 40 x + ( 5 – x ) × 60 = 240 , we get 40 x + 300 – 60 x = 240 ⇒ 20 x = 60 or x = 3 hours answer : c
divide(subtract(multiply(60, 5), 240), subtract(60, 40))