Final answer:
Colin, who had the largest share of the pizza (5 out of 12 parts), donated 1/3 of his share to charity. By calculating 1/3 of 5/12, we find that Colin has donated 5/36 of the entire pizza.
Step-by-step explanation:
The question asks about the sharing of a pizza in a specific ratio and then further distributing a part of that share to charity. When Anne, Berry, and Colin share a pizza in the ratio of 3:4:5, and if Colin shares 1/3 of his part to charity, we want to determine what fraction of the whole pizza Colin has given away. Colin has the largest share, which is 5 parts out of the total 12 (3+4+5=12) parts of the pizza.
To calculate the fraction of the pizza he donated, we take 1/3 of his share (5/12 of the pizza) and get the final fraction of pizza given to charity.
To find Colin's donation fraction: 1/3 of 5/12 = (1/3) * (5/12) = 5/36. So, Colin has shared 5/36 of the entire pizza to charity.