Let's carefully examine each step of Rahul's work to identify where the first mistake occurred.
The original expression is:
[tex]\[ 7(8.5 - 1.5) + 8 + 2 \][/tex]
Step 1:
Rahul evaluates the expression inside the parentheses:
[tex]\[ 8.5 - 1.5 = 7 \][/tex]
So, the expression becomes:
[tex]\[ 7(7) + 8 + 2 \][/tex]
This is correct.
Step 2:
Next, Rahul performs the multiplication:
[tex]\[ 7 \times 7 = 49 \][/tex]
So, the expression becomes:
[tex]\[ 49 + 8 + 2 \][/tex]
This is also correct.
Step 3:
Now, Rahul adds the terms together:
[tex]\[ 49 + 8 = 57 \][/tex]
The expression then becomes:
[tex]\[ 57 + 2 \][/tex]
So far, everything is still correct.
Step 4:
Finally, Rahul adds the remaining numbers:
[tex]\[ 57 + 2 = 59 \][/tex]
However, he writes down 28.5, which is incorrect.
The first mistake occurred in Step 3.
Therefore, Rahul made his first mistake in Step 3.
