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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?

Verified Answer :

KalebJS

Reverse engineer the original value
Step 1.) 34 * 3 = 102
Step 2.) 102 + 9 = 111
Using 111 use proper sequence to derive solution
Step 3.) 111 - 3 = 108
Step 4.) 108 / 9 = 12
12 is the solution

Answer:

Step-by-step 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

\(\frac{x-3}{9}\)

Now let's see the operation that Cindy did

  • She subtracted 9

\(x-9\)

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

\(\frac{x-9}{3}=34\)

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

\(\frac{x-9}{3}= 34\\ x-9= 3(34)\\x-9= 102\\x=102+9\\x= 111\)

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.

\(\frac{x-3}{9}\\\frac{111-3}{9} \\\frac{108}{9}= 12\)

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