Sure, let's analyze the steps Marcus took to solve the equation and understand where he might have made an error.
1. Original Equation:
[tex]\[
2.5b = 5
\][/tex]
This equation is correctly set up. Nothing wrong here.
2. Dividing both sides by 2.5 to isolate [tex]\( b \)[/tex]:
[tex]\[
\frac{2.5b}{2.5} = \frac{5}{2.5}
\][/tex]
Simplifying the left-hand side, we get:
[tex]\[
b = \frac{5}{2.5}
\][/tex]
3. Calculating [tex]\( \frac{5}{2.5} \)[/tex]:
This is the crucial step. Marcus needs to compute:
[tex]\[
\frac{5}{2.5}
\][/tex]
To do this division correctly:
[tex]\[
\frac{5}{2.5} = 2
\][/tex]
So, [tex]\( b = 2 \)[/tex].
4. Marcus’ Result:
Marcus wrote [tex]\( b = 3 \)[/tex]. This is incorrect because:
[tex]\[
b = 2
\][/tex]
Therefore, Marcus made his mistake during the calculation step. The correct calculation of [tex]\( \frac{5}{2.5} \)[/tex] should yield 2, not 3.
So, the correct answer is:
(B) Calculating
