Question

Gabi tried to solve an equation step by step.

\[\qquad\begin{aligned}
0.1(0.5m+6)&=2\\\\
\\
0.5m+6&=20&\green{\text{Step } 1}\\\\
\\
0.5m&=14&\blue{\text{Step } 2}\\\\
\\
m&=7&\purple{\text{Step } 3}\\\\
\end{aligned}\]
Find Gabi's mistake.
Choose 1 answer:
A
\[\green{\text{Step }1}\]
B
\[\blue{\text{Step }2}\]
C
\[\purple{\text{Step }3}\]
D
Gabi did not make a mistake.

Answer 1

C

Step 3 is wrong. From 0.5m = 14, m = 14 ÷ 0.5 = 28 (not 7). Checking: 0.1(0.5·28 + 6) = 0.1(14 + 6) = 2.