Question

A person was weighing $102.1kg$ last week and gained $0.28kg$ this week. His weight as of now is correctly expressed as :

• A. $102.38kg$
• B. $102.3kg$
• C. $102.4kg$
• D. $102kg$

Answer 1

The correct option is C $102.4kg$

We know that number of significant figures after addition will be equal to least number of significant figures present in any of the operand.
Therefore total weight after weight gain is $102.1+0.28=102.38kg$
Now least number of significant figure present after the decimal in the operand is 1, present in $102.1kg$ .
Therefore, the number of significant figures present after the calculation should also be $1$ after the decimal. Hence, when we round the answer $102.38$ becomes $102.4kg$
Therefore correct answer is option (C)