Sarah can bicycle a loop around the north part of lake washington in 2 hours and 40 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?

Time equal to distance divided by the speed. In this question, Sarah need 2 hours and 40 minutes(or 160 minutes)  to loop around the north part of Lake Washington. The time for the same distance cutted by 6 minutes if the speed increased by 1km/h. The calculation would be:

time= distance/speed

distance= time*speed=

distance1= distance2

time1*speed1= time2*speed2

160min*speed1= (160min-6min)*(speed1+1km/h)

160 speed1= 154 speed1 + 154km/h

160 speed1- 154 speed1 = 154km/h

speed1= 154km/h /6= 25.67km/h

answer: 177/8

step-by-step explanation: