Step-by-step explanation:
A motorist drives 146km at a certain average speed she then increases the speed by 9km/h and takes the same time to travel the next 164km.
find her speeds for both parts of the journey.
:
let s = his original speed
then
(s+9) = the increased speed
:
Write a time equation; time = dist/speed
146%2Fs = 164%2F%28%28s%2B9%29%29
cross multiply
164s = 146(s+9)
164s = 146s + 1314
164s - 146s = 1314
18s = 1314
s = 1314/18
s = 73 km/h is his original speed
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