Math Gold Medalist

Lor

2022 AMC 8 

Problem 16

Four numbers are written in a row. The average of the first two is $21,$ the average of the middle two is $26,$ and the average of the last two is $30.$ What is the average of the first and last of the numbers?

$\textbf{(A) } 24 \qquad \textbf{(B) } 25 \qquad \textbf{(C) } 26 \qquad \textbf{(D) } 27 \qquad \textbf{(E) } 28$

Translating Word Problems Into Equations

Changing Average to Sum

a+b=42

b+c=52

c+d=60

Add first and third equations and subtract second equation.

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   Solution