Question

cindy was asked by her teacher to subtract 3 from a certain number and then divide the result by 9. Instead, she subtracted 9 and then divided the result by 3, giving an answer of 34. what would her answer have been if she had worked the problem correctly?

Answer 1

Explanation:

First let's look at the operation that the teacher asked Cindy

• Subtract 3 from a certain number

Let's call the certain number X

`3-x`

• Divide the result by 9

`(x-3)/(9)`

Now let's see the operation that Cindy did

• She subtracted 9

`x-9`

• Divided the result by 3, giving an answer of 34

`(x-9)/(3)=34`

From the operation that Cindy did we can clear the value of x

`(x-9)/(3)= 34\\ x-9= 3(34)\\x-9= 102\\x=102+9\\x= 111`

Now we substitute the value of x obtained in the operation that the teacher said to find the answer if she had worked the problem correctly.

`(x-3)/(9)\\(111-3)/(9) \\(108)/(9)= 12`