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# help please thanks :) <3

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A cyclist rides 30 km at an average speed of 9 km per hour. At what rate must the cyclist cover in the next 10 km in order to bring the overall average speed up to 10 km per hour?

Jul 13, 2021

#1
+208
+2

Remember, distance=rate*time

Distance                 Rate              Time

First part of trip        30                       9                  30/9

Last Part of trip        10                       x                  10/x

Whole trip                40                       10                  4

(Time for the first part of the trip) + (time for the second part of the trip) = (total time of trip)

$$\frac{30}{9}+\frac{10}{x}=4 \\30x+90=36x \\-6x=-90 \\x=15$$

so the cyclist's rate must be 15 kph in the next 10 km in order to bring the overall speed up to 10 km per hour

JP

Jul 13, 2021

#1
+208
+2

Remember, distance=rate*time

Distance                 Rate              Time

First part of trip        30                       9                  30/9

Last Part of trip        10                       x                  10/x

Whole trip                40                       10                  4

(Time for the first part of the trip) + (time for the second part of the trip) = (total time of trip)

$$\frac{30}{9}+\frac{10}{x}=4 \\30x+90=36x \\-6x=-90 \\x=15$$

so the cyclist's rate must be 15 kph in the next 10 km in order to bring the overall speed up to 10 km per hour

JP

JKP1234567890 Jul 13, 2021
#2
+1

tysm

<3

Guest Jul 13, 2021
#3
+124525
+1

Very nice, JP    !!!!!!

CPhill  Jul 13, 2021
edited by CPhill  Jul 13, 2021
edited by CPhill  Jul 13, 2021