Karen’s pencil is 12 cubes long. If she has two more pencils that are each 12 cubes long, how many cubes long are all three pencils together?

The correct answer is: 36

Step by step solution:
Length of each pencil = 12 cubes
Length of all 3 pencils together = 12 + 12 + 12 = 36 cubes.
So, the length of all 3 pencils together is 36 cubes.
Hence, option(a) is the correct option.

In this question, instead of adding the lengths of all the three pencils we could simply multiply the length of one pencil by the number of pencils (i.e., 3)
Thus, length of the 3 pencils = 12 cubes x 3 = 36 cubes
Hence, option(a) is the correct option.