Question

Sarah can bicycle a loop around the north part of Lake Washington in 2 hours and 50 minutes. If she could increase her average speed by 1 km/hr, it would reduce her time around the loop by 6 minutes. How many kilometers long is the loop? (Round your answer to two decimal places.)

this is what I did
v= 2.8333hr
v+1=2.733hr
D=v*2.8333=(v+1)*2.733
(v+1)/v=2.8333/2.7333=1.03659
v+1=1.03659
0.03659v=1
v=27.33*2.8333=77.43km and it said that I was wrong

Answer 1

17/6 s = (17/6 - 1/10)(s+1)
s = 82/3 = 27.33 km/hr
so the distance is 697/9 = 77.44 km
Maybe the rounding caused the discrepancy in the 2nd decimal place.
check:
17/6 * 82/3 = 697/9
(17/6 - 1/10)(82/3 + 1) = 697/9

Answer 2

thanks thats worked