Thanks for all your help, it has shown that i am just as smart as if not SMARTER than a fifth grader.?

Question

ok with your help my daughter has seen that I do have the right answers just that i do not show all the steps on how to get the answers and that is what she needs. I just know the answers and not so much how to explain to her how to get them.

Like in this problem 84 people attended a concert. This was 70% of the number expected to attend. How many people were expected to attend?

I know the answer, with rounding, is aproximately 59. I cannot explain to her steps on how to get the answer though. maybe you can help us again. Thank you :)

Answer 1

If 84 is 70% of those expected to attend, then the number expected to attend is 120.

.7x = 84

.7x/.7 = 84/.7

x = 120

Answer 2

You always set up percentage questions as follows:

IS/OF = %/100

So this question is asking 84 IS 70% OF what number?

84/x = 70/100.

Cross-multiply and solve for x, so you get 70x = 8400

Divide both sides by 70 and you get x = 120.  120 people were expected to show up.

Think about the answer of 59.  If 59 people were expected to attend but 84 showed up, that would be greater than 100% of the people expected to show up.

QED

Answer 3

84/70 = x/100

multiply both sides by 100

8400/70 = x

840/7 = x

120 = x

120 people were expected to attend.  If 84 represents 70%, the number expected has to be larger than 84, so 59 cannot be the correct answer.

Did you write the problem backwards?

84 were expected, only 70% showed up?

84/100 = x/70

multiply both sides by 70

5880/100 = x

58.8 = x   hence your rounded 59.

Since the first way gives a whole number, at 5th grade, I'm thinking that's the way to do it.

Good luck :D