Answer:
a) 99.95 grams are remaining after 4 years.
b) The percent of carbon-14 remaining is about 99.95%
Step-by-step explanation:
The amount of carbon 14 remaining after t years is given by the following equation:

a) Amount remaining after 4 years.

99.95 grams are remaining after 4 years.
b) Percentage remaining after 4 years:

The percent of carbon-14 remaining is about 99.95%