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Congratulations!!! You made in through our 30-Day Data Sufficiency Challenge! This is the  last post in this series (but certainly won’t be my last post about DS!) 

This series was designed to help you step up your Data Sufficiency practice while we all spend a little extra time at home during the coronavirus situation. If you missed any of the previous questions, click on the tag “Social Distancing DS Challenge” at the bottom of this post to see all of the questions in this series! 

Question #30

A 40-foot long platform connects two adjacent buildings, and the platform is made up of a one-plank-wide strip of square-shaped planks. How many planks comprise the platform?

(1) Each plank has a diagonal of 5√2 feet.

(2) Each plank has a width of 5 feet.

Explanation

Statement (1) is sufficient because we can determine that the square-shaped planks have sides of length 5. 8 square planks of length 5 would make a 40-foot long sidewalk. Remember that the diagonal of a square is length * √2.

Statement (2) provides the same information as Statement 1, and knowing the width (or length) of each plank will tell you the total number of planks needed to make up the total platform.

The correct answer is (D).