Final answer:
The estimated sum of 39.75 and 47.6 is approximately 88, but the closest answer choice offered is 87.35 (option b).
Step-by-step explanation:
The estimated sum of the numbers 39.75 and 47.6 is achieved by rounding each number to the nearest whole number before adding. Rounding 39.75 to 40 and 47.6 to 48 gives us an estimated sum of 40 + 48, which equals 88. The closest answer choice to our estimated sum of 88 is option b) 87.35, although it is slightly less than our estimate.