It will take her 30 more minutes to finish her walk for a total of 45 minutes.  45 minutes of 60 minutes in an hour is the same as $\displaystyle \frac{3}{4}$.

The factors of 12 are 1, 12, 3, 4, 2, and 6.  The sum of them is when you add all of them together. $\displaystyle 1 + 12 + 3 + 4 + 2 + 6= 28$.

If $\displaystyle \frac{3}{4}$ are male, then $\displaystyle \frac{1}{4}$ of the children in the class are female $\displaystyle \left( 1-\frac{3}{4}\right)$.  

If this is true, then $\displaystyle \frac{1}{4}$ times the total number of students in the class will give you the number of females.  

$\displaystyle \frac{1}{4} * 28 = 7$

The best way to think about this problem is to divide the total number of people into parts. Since there are 5 parts women to 3 parts men, it's best to divide the total into 8 parts.  Dividing 56 into 8 parts gives you 7.  7 is your multiplier.  Now take your multiplier (7) and multiply it by your ratios.  

This give you $\displaystyle 5\cdot 7$ and $\displaystyle 3\cdot 7$ or $\displaystyle 35$ and $\displaystyle 21$.  These are the number of women and men, respectively.  

The difference between 35 and 21 is 14.

We can solve this problem by backsolving, meaning plugging in the answer choices. 

If we plug in 7 for the dog's age, that means that in 3 years, the dog will be 10. 

That also means that the cat is 3 since the dog is 4 years older. 

The sum of 10 and 3 is 13, so the answer choice of 7 is the correct answer. 

If $\displaystyle \frac{2}{3}$ are male, then $\displaystyle \frac{1}{3}$ of the puppies in obedience training are female. Because:

 $\displaystyle \bigg(1 - \frac{2}{3}\bigg)=\frac{3}{3}-\frac{2}{3}=\frac{1}{3}$.

Now we can write the following proportion and solve.

$\displaystyle \frac{1}{3}=\frac{x}{36}$

$\displaystyle \bigg(\frac{1}{3}\bigg)36=12$

The best way to think about this problem is to divide the total number of people into parts. Since there are $\displaystyle 4$ parts doctors to $\displaystyle 7$ parts nurses, it's best to divide the total into $\displaystyle 11$ parts. Dividing $\displaystyle 121$ into $\displaystyle 11$ parts gives you $\displaystyle 11$. Therefore, $\displaystyle 11$ is your multiplier. Now take your multiplier and multiply it by your ratios.

This gives you $\displaystyle 4 \cdot11=44$ and $\displaystyle 7\cdot 11=77$. These are the number of doctors and nurses, respectively.

To find how many more nurses than doctors there are we take the difference:

$\displaystyle 77-44=33$

Therefore, there are $\displaystyle 33$ more nurses than doctors.

To solve:

Divide the total amount of Alice's allowance ($2.40) by the price for each snack ($ .60)

$\displaystyle 2.40\div 0.60=4$

Alice would be able to buy 4 snacks.

On Tuesday, Steve ate 50% (half) of the 80%, which is 40%.  Steve has eaten 20% on Monday and 40% on Tuesday, so there is 40% left over.

Divide 90 hours by 30 days in the month:

$\displaystyle 90 \div 30= 3$

Answer: Nicolas needs to train 3 hours a day.