9514 1404 393
Answer:
525 km
Step-by-step explanation:
Let d represent the distance to the town. Let s represent the nominal speed of the car. The relation between time, speed, and distance is d = st.
t1 = d/s
t2 = d/(s+15)
t1 : t2 = 6 : 5 . . . increasing the speed reduces the time
Substituting for t1 and t2, we have ...
(d/s)/(d/(s+15)) = 6/5
(s +15)/s = 6/5
1 +15/s = 1 +1/5
s = 5·15 = 75 . . . . nominal speed in km/h
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Decreasing the speed increases the time.
d/75 +(105/60) = d/(75-15)
d(60/75) +105 = d . . . . . . multiply by 60
105 = d/5 . . . . . . . . . . . subtract 4/5d
525 = d . . . . . . . . . . multiply by 5
The distance traveled by the car is 525 km.
