First of all,
The total weight of the six dogs are:
71+34+15+23+18+56=217 pounds
Then, we know that the average weight of the seven dogs are 40 pounds, so the total weights of the seven dogs are:
40×7=280 pounds.
Lastly, we know that the six dogs weights are 217 pounds and the total weight of the seven dogs are 280 dogs, so the seventh weight of the dog is:
280-217=63 pounds. As a result, the seventh weight of the dogs at the vet is 63 pounds. Hope it help!
Sixteen point nine hundred eighty five
First of all, you can simplify the 4 at the numerator and the 14 at the denominator (they're both multiple of 2):

Now, rationalize a denominator means that you have to get rid of the square root, in order to have an integer denominator.
To do so, remember that you can always multiply any number by 1 without changing its value, and you can always think of 1 as a fraction where numerator and denominator are equal:

For this case we have to take into account the following conversions:

Let's first transform the expression to miles per seconds squared:

Then, we transform the result to miles per minute squared.
We have then:
Answer:
the rate in miles/min^2 is: