In chemistry lab, students started with $150.13 \mathrm{~g}$ of a substance. They were to heat the substance and reweigh it after $5,10,15$, and 20 minutes had passed and record the weights. The students recorded the following data:
\begin{tabular}{|c|c|}
\hline minutes passed & grams left \\
\hline 5 & 149.65 \\
\hline 10 & 123.93 \\
\hline 15 & 100.22 \\
\hline 20 & 89.96 \\
\hline
\end{tabular}
If the students round each weight measurement to the nearest tenth, what is the approximate total change in weight of the substance after 20 minutes?
Answer
The approximate total change in weight of the substance after 20 minutes is $60.17 \mathrm{~g}$
Step 1 ：Subtract the initial weight from the weight after 20 minutes: $150.13 \mathrm{~g} - 89.96 \mathrm{~g} = 60.17 \mathrm{~g}$
Step 2 ：The approximate total change in weight of the substance after 20 minutes is $60.17 \mathrm{~g}$
