Question

A magazine ad states that 4 out of 7 doctors recommend Flash toothpaste. if 1400 doctors were surveyed, how many doctors recommended flash toothpaste?

Answer 1

Total number of doctors who recommend Flash toothpaste = 800

Explanation:

Give:

Total doctors surveyed = 1400

Out of 7, 4 doctors recommend Flash toothpaste.

To find the total number of doctors who recommend Flash toothpaste.

Solution:

As 4 out of 7 doctors recommend Flash toothpaste, so we will divide the total number of doctors into groups of 7.

Total number of groups formed will be =
`(1400)/(7)` = 200

We know that on average 4 doctors in each group recommend Flash toothpaste.

So, to find total number of doctors who recommend Flash toothpaste we will multiply.

Total number of doctors who recommend Flash toothpaste =
`4* 200`= 800

Answer 2

The number of doctors recommended flash toothpaste 800.

Explanation:

Given:

A magazine ad states that 4 out of 7 doctors recommend Flash toothpaste.

Now, to find the numbers of doctors recommended flash toothpaste if 1400 doctors were surveyed.

Let the number of doctors recommended be
`x`.

And the total number of doctors surveyed were 1400.

So, as given 4 out of 7 doctors recommend flash toothpaste.

So, 4 equivalent to 7 =
`(4)/(7)`.

And,
`x` equivalent to 1400 =
`(x)/(1400)`.

Thus, we set the proportion and solve by cross multiplication method:

`(4)/(7) =(x)/(1400)`

By cross multiplying we get:

`5600=7x`

Dividing both sides by 7 we get:

`800=x`

`x=800.`

Therefore, the number of doctors recommended flash toothpaste 800.