David travels from Building A to Building B. He can either cycle
for 19 minutes and drive for 8 minutes or drive for 10 minutes
and cycle for 13 minutes. If he cycles all the way, how long
does he need to arrive at City B?

Respuesta :

Answer:

43 minutes

Step-by-step explanation:

  • Let cycling speed be x and driving speed be y

Equations as per given, considering same distance in both cases:

  • 19x + 8y = 13x + 10y
  • 19x - 13x = 10y - 8y
  • 6x = 2y
  • 3x = y

We see that driving speed is 3 times greater than cycling speed

Then 8 minutes driving = 8*3= 24 minutes of cycling, or 10 minutes of driving = 10*3= 30 minutes of cycling:

  • 19 + 24 = 43 minutes or
  • 13 + 10*3 = 43 minutes is the time to cycle between A and B