Question

Mr.H teaches 5 classes. The mean number of students per class is 17.4. If he teaches one more class, the mean increases to 18.5. How many students are in the sixth class?

Answer 1

interesting

Answer 2

let's say x is the total of the five classes

so you have \[\frac x5 = 17.4\]

agree?

Answer 3

Hmm. I'm not sure. o.o.

Answer 4

it said mean number students per class is 17.4

so you get the total students of the five classes and divide it by 5. that's how you get the mean right?

Answer 5

Oh yes. I agree.
It's the way you say 'total of the five classes" that confused me.

Answer 6

okay so now it's settled that \[\frac x5 = 17.4\]
and x is the total number of students in the 5 classes

so now get x

Answer 7

17.4 * 5 = 87

x = 87 ?

Answer 8

right. now before i proceed, i need to clarify something

Answer 9

Sure, what is it?

Answer 10

the mean increases is 18.5

this is ambiguous...is that mean increases TO? or mean increase is?

Answer 11

to* My bad. >_>

Answer 12

then the next equation would be \[\frac{87 + y}6 = 18.5\]

where y is the total number of students in the sixth class

Answer 13

you get why that is the equation right?

Answer 14

^ that looks like the right equation to me

Answer 15

Yes, because there is a total of 87 students in the 5 classes, and an 'y' amount of student in the 6th class.
Divide that by the total amount of class, 6. And it would be equal to 18.5 because that is the new mean after the 6th class is added.

Answer 16

right

Answer 17

Let see, to solve this you multiply 6 by 18.5 to get 111.
So it should look like: 87 + y = 111
Subtract 87 to get: y = 24

There is 24 students in the 6th class.

Answer 18

Alright, thanks. Now it make sense. Just an extra more step to solve this.

Answer 19

that's the reason for the "interesting" comment