please help with this problem

Question

During a 5 year period, 35% of snowstorms in a certain city caused power outages. Thirty-nine of the snowstorms did not cause power outages. Find the total number of snowstorms in this city over the 5- year period. Mymathuniverse

Answer 1

If 35% of the snowstorms caused power outages, that means that 65% did not cause outages.  It's important to know that 65% did not cause outages because the only number you're given, 39, is the number of snowstorms that did not cause outages.

 

So, now you know that 39 is 65% of the total.  From that, we can make a math equation to find the answer.  The math equation we want to write is "39 is 65% of what number?"

We will write 65% as 0.65. 

We can use the equals sign to replace the word "is."

We can use N instead of the words "what number."

We can use the multiplication symbol "*" instead of the word "of."

 

In word form:

39 is 65% of what number?

 

In math equation form:

39 = 0.65 * N

 

So we just have to solve 39 = 0.65N

Dividing both sides by 0.65 gives us N = 60

So there were a total of 60 snowstorms over that 5-year period.

I hope that helps!