Question

I need some help with this question here
Roshni cycles 2 km at y km/h and then runs 4 km at (y-4) km/h.
The whole journey takes 40 minutes.
i) Write an equation in y and show that it simplifies to $y^{2} -13y+12=0$
Please answer as soon as possible. Many thanks in advance!

Answer 1

Answer:speed is 12kn/hr

Step-by-step explanation:

2 / y + 4 / [ y - 4 ] = 2/3

6 [ y - 4 ] + 12 y = 2y [ y - 4 ]

18y - 24 = 2y² - 8y

2y²  -  26y + 24 = 0

y² - 13y + 12 = 0

[ y - 12 ] [ y - 1 ] = 0

Speed is 12 km/h