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Fri Aug 28, 2020 7:27 am

Official Guide

A rope 40 feet long is cut into two pieces. If one piece is 18 feet longer than the other, what is the length, in feet, of the shorter piece?

A. 9
B. 11
C. 18
D. 22
E. 29

OA B

APPROACH #1: Algebra
Let x = the length of the shorter piece
So, x + 18 = the length of the longer piece

Since the lengths of the two pieces must add to 40 feet, we can write: x + (x + 18) = 40
Simplify: 2x + 18 = 40
Subtract 18 from both sides: : 2x = 22
Solve: x = 11

Answer: B
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APPROACH #2: Test the answer choices

Start with the middle answer choice C

C) 18
If the shorter piece is 18 feet long, then the longer piece is 36 feet long
Sum of lengths = 18 + 36 = 54
NO GOOD. We want a sum of 40 feet (as per the question)
So, we can ELIMINATE C.
Also, since we need the two pieces to be SHORTER, we can also ELIMINATE D and E

Now try answer choice B
B) 11
If the shorter piece is 11 feet long, then the longer piece is 29 feet long
Sum of lengths = 11 + 29 = 40
PERFECT!!!

Answer: B

Cheers,
Brent