Step-by-step explanation:
<u>Formula:</u>

r represents the radius.
The radius is 1/2 of the diameter.
Since 1/2 of 16 is 8, 8 is our radius.
<u>Substitute:</u>

<u>Solve:</u>


Find the distance of each trip:
68 km / 34 trips = 2 km per trip
Divide total distance by distance per trip:
348 km / 2 km per trip = 174 trips
Answer: 174 trips
There would be 19.2 cups. At least from what I am thinking of. So you would get 19 cups and about a fourth of another cup. I hope this helps! :)
See https://web2.0calc.com/questions/need-help-now_10.