Question

What is the rule in the input/output table? A) add 4 B) subtract 4 C) divide by 2 D) multiply by 2 | inputs | 4 6 and 8 | outputs | 8 10 and 12

Answer 1

Let's build a table for each option: if the inputs are 4, 6 and 8, adding four to each of these leads to

$\begin{array}{c|c}\text{in}&\text{out}\\4&8\\6&10\\8&12\end{array}$

Subtract 4 gives

$\begin{array}{c|c}\text{in}&\text{out}\\4&0\\6&2\\8&4\end{array}$

Dividing by 2 gives

$\begin{array}{c|c}\text{in}&\text{out}\\4&2\\6&3\\8&4\end{array}$

Multiplying by 2 gives

$\begin{array}{c|c}\text{in}&\text{out}\\4&8\\6&12\\8&16\end{array}$

So, as you can see, the only way to obtain the desired outputs is "add 4"

Answer 2

Input: 4, 6, 8

Output: 8, 10, 12

8-4 = 4

10-6 = 4

12 - 8 = 4

The rule is add 4 to the input.

The answer is A.