Question

If you multiply a number by 3 and then add 40, the result is the same as if you first add 17 and then multiply by 2. What is the result if you subtract 9 from the number and then multiply by 4?
a) -60
b) -72
c) -84
d) -108

Answer 1

Hint: Let us assume that the number is x. It is given in the question that when we add 40 to the 3 times of the number, it gives the same answer when we multiply the sum of the number and 17 by 2. So, we have two equations in terms of x.
Solve the above equations and find the value of x and substitute in another equation that is asked.

Complete step by step answer:
According to the question, it is said that when we add 40 to the 3 times of the number, it gives the same answer when we multiply the sum of the number and 17 by 2.
So, we have two equations in terms of x.
$\begin{align}
  & 3x+40......(1) \\
 & 2\left( x+17 \right)......(2) \\
\end{align}$
So, by equating equation (1) and (2), we get:
$\begin{align}
  & 3x+40=2\left( x+17 \right) \\
 & 3x+40=2x+34 \\
 & x=-6......(3)
\end{align}$

Now, we need to find the value when we subtract 9 from the number and multiply the result by 4.
i.e. $4\left( x-9 \right)$
Substitute the value of x from equation (3), we get:
$\begin{align}
  & \Rightarrow 4\left( -6-9 \right) \\
 & \Rightarrow 4\times -15 \\
 & \Rightarrow -60 \\
\end{align}$

So, the correct answer is “Option A”.

Note: Be careful while reading the question. The language might confuse you. As in given in the question, multiply a number by 3 and then add 40.
The equation for this is $3x+40$
But some might make a mistake here as $3\left( x+40 \right)$