Alice is in a 20 km running race .she always runs the first half at an average speed of 2km/h faster than the second half . a ) let x represent her speed in the first half .determine a simplified expression in terms of x for the total time needed for the race .b) if Alice runs the first half at 10km/hr .how long will it take her to run the race ?
can somebody help me with this one ,it's my assignment,thank you
can somebody help me with this one ,it's my assignment,thank you
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a) 10/x+10/(x-2)
b) 10/10+10/(10-2)
1+10/8
1+1.25
2.25 hr.
b) 10/10+10/(10-2)
1+10/8
1+1.25
2.25 hr.
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If x is av. speed of 1st half it is 2km/h faster than second half then av. speed of 2nd half is x-2.distance of 1st half is 10km.
Speed=distance/time(t)
therefore time of 1st half is 10/x and for the 2nd half is 10/(x-2).total time=[10/x+10/(x-2)
if av speed of 1st half is 10 dat for 2nd half is 8.time for 1st half is 10/10 which is 1hr.dat for 2nd half is 10/8.therefore time taken to cover total distance is 1+10/8=9/4.is that ok?
Speed=distance/time(t)
therefore time of 1st half is 10/x and for the 2nd half is 10/(x-2).total time=[10/x+10/(x-2)
if av speed of 1st half is 10 dat for 2nd half is 8.time for 1st half is 10/10 which is 1hr.dat for 2nd half is 10/8.therefore time taken to cover total distance is 1+10/8=9/4.is that ok?