Final answer:
By adding the fractions 1/3 and 1/4 to find the total wall painted on Monday and Tuesday, we find that Phoebe painted 5/12 of the wall on Wednesday, as it is the remaining fraction after subtracting 7/12 from the whole wall.
Step-by-step explanation:
Phoebe painted 1/3 of a wall on Monday and 1/4 of the wall on Tuesday. To determine what fraction of the wall she painted on Wednesday, we need to calculate the total fraction painted by combining Monday's and Tuesday's fractions.
To find the combined fraction, we need to add 1/3 to 1/4. To add fractions with different denominators, we find a common denominator. The least common denominator (LCD) for 3 and 4 is 12. We convert each fraction to have a denominator of 12:
Now we add the fractions:
4/12 + 3/12 = 7/12
Thus, Phoebe painted 7/12 of the wall on Monday and Tuesday combined. Since the entire wall is considered 1 (or 12/12), the fraction painted on Wednesday is the remainder:
1 (entire wall) - 7/12 (painted on Monday and Tuesday) = 5/12
Therefore, Phoebe painted 5/12 of the wall on Wednesday.