Don't let it get to ya. If they didn't think you're capable of answering this question, they wouldn't ask you. So they know your abilities better than you do.
We don't know the unknown number, so in order to discuss it, we have to give it some kind of a name. We could call it 'x', 'y', 'Ana, 'Q', or 'Ralph'. Let's call it 't'.
The unknown number . . . . . t
Five times the number . . . . . 5t
Nine less than five times the number . . . . . 5t - 9 . Hold on to this quantity.
Twice the number . . . . . 2t .
Three more than twice the number . . . . . 2t + 3. Hold on to this quantity too.
The question says that these two quantities are equal. So the equation is
5t - 9 = 2t + 3 . This is the equation in both choices 'c' and 'd' . I guess we'll have to solve it to find out which choice is the correct one.
The equation is . . . . . 5t - 9 = 2t + 3
Add 9 to each side . . . . . 5t = 2t + 12
Subtract 2t from each side . . . 3t = 12
Divide each side by 3 . . . . . t = 4 .
It looks like choice-d is the winner.
on the matrix gives![\left[\begin{array}{cc|c}5&5&5\\1&-\dfrac23&5\end{array}\right]\to\left[\begin{array}{cc|c}1&-\dfrac23&5\\5&5&5\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7Cc%7D5%265%265%5C%5C1%26-%5Cdfrac23%265%5Cend%7Barray%7D%5Cright%5D%5Cto%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7Cc%7D1%26-%5Cdfrac23%265%5C%5C5%265%265%5Cend%7Barray%7D%5Cright%5D)
