A boat can travel 16 Kilometers per hour in still water. The boat travels 15 kilometers down a river and then 15 kilometers up stream. The entire trip takes 5.5 hours. Which equation describes the current, c, of the river?

a)
[tex] \frac{16}{15 + c} + \frac{16}{15 - c} = 5.5 [/tex]
b)
[tex] \frac{5.5}{16 + c} + \frac{5.5}{16 - c} = 15 [/tex]
c)
[tex] \frac{5.5}{15 + c} + \frac{5.5}{15 - c} = 16 [/tex]
d)
[tex] \frac{15}{16 + c} + \frac{15}{16 - c} = 5.5[/tex]


Sagot :

Answer:

d)

Step-by-step explanation:

the sites of the boat alone is 16 km/h.

downstream and upstream the effective speed is then influenced plus and minus by the current.

the distance traveled is 15km.

as speed = distance/time

then distance / speed = distance / (distance/time) = time

and we know the time it takes : 5.5 hours.

so, only answer d uses the right values in the "right places".