Answer:
Mrs. Towle's husband will be able to build the fence before Christmas, and she will be able to get a puppy for him.
Explanation:
Mrs. Towle's husband can build the fence alone in 12 days and together with their normal working schedules in 4 days. Mrs.
Towle decided to get a puppy for her husband exactly 7 days before Christmas.
First, let's determine the rate at which Mrs.
Towle's husband and his wife can build the fence together per day:
If Mrs. Towle's husband can build the fence alone in 12 days, his daily rate is 1/12 of the fence.
If they can build the fence together in 4 days, their combined daily rate is 1/4 of the fence.
Now, let's calculate the portion of the fence they can build in 7 days:
Mrs. Towle's husband alone: 7 * (1/12) = 7/12 of the fence
Together with their normal working schedules: 7 * (1/4) = 7/4 of the fence
Since 7/4 is greater than the entire fence, they can complete the fence in 7 days.
Therefore, Mrs. Towle will be able to get a puppy for her husband before Christmas.
Thus, Mrs. Towle's husband will be able to build the fence before Christmas, and she will be able to get a puppy for him.