Question

Kevin and Amy are working on an experiment in the science lab. They start with 2.3 grams of oil and add water to get exactly 4.21 grams of solution. To find the amountof water added, they subtract the weight of the oil from theweight of the solution. Kevin calculates the difference tobe 3.98 grams; Amy calculates it to be 1.91 grams.Who is correct, and why? 4.21 4.21Kevin -2.3 Amy -2.30 ——— ——— 3.98 1.91A. Amy is correct. Kevin did not line up the decimals correctly.B. Kevin is correct. Amy did not line up the decimals correctly.C. Kevin is correct. Amy did not regroup properly.D. Amy is correct. Kevin did not regroup properly.

Answer 1

A. Amy is correct. Kevin did not line up the decimals correctly.

Step-by-step explanation:

Let the grams of water added = x

`\begin{gathered} 2.3+x=4.21 \\ \implies x=4.21-2.30 \\ x=1.91\text{ grams} \end{gathered}`

From the workings shown, we see that Amy is correct as Kevin did not line up the decimals correctly.

The correct choice is A.