Question

Question #4c400

Answer 1

25% of the club is 40 children. 25% is the same as `1/4`
100% is 160 children.

Explanation:

It is tempting to write 25% = 40, but mathematically this is horrible!
(0.25 is certainly NOT the same as 40)

What we do mean is that 25% of an unknown amount is 40.

Using algebra: `25/100 xx x = 40` which we can solve...

`x = 40 xx 100/25`

`x = 40 xx 4`

`x = 160`

Or draw a small diagram (a rectangle will work fine) to be able to visualise the scenario.

Divide the rectangle into 4 equal sections, each one represents 25% or `1/4` of the whole .

Fill in the number 40 in each part, because that is the number of children that make up `1/4` of the total.

You will easily see that the total is made up of 4 x 40 = 160 children.

Answer 2

B. 160

Explanation:

We know that 40 children is equal to 25% of the total. Let's make the total (which we want to find) `x`.

From this we can write an equation.

`40 = 25/100 x`

To find `x`, we'll have to move all the numbers to the other side.

Let's move the 100 first. Since it's being divided, once we move it to the other side it will be multiplied instead.

`40xx100 = 25x`
`4000=25x`

Now we move the 25.
`25x` means `25xx x`, so when we move it to the other side it will be divided.

`4000-:25=x`
`160=x`

Hope that helps!