To find the estimate, round 25.62 ounces to the nearest whole number, which would be 26 ounces. Divide that by the 4 friends and you'll get about 6.5 ounces per friend.
To find the actual answer, simply divide 25.62 ounces by 4 ounces.
Your answer for Part C should elaborate on the idea that your answer is close to the estimate, so the estimate is reasonable (add more detail to this to receive full credit, this is just so get a sense of the concept).
