Question

A textbook store sold a combined total of 252 chemistry and physics textbooks in a week. The number of chemistry textbooks sold was 78 more than the number of physics textbooks sold. How many textbooks of each type were sold?Number of chemistry textbooks sold:Number of physics textbooks sold:

Answer 1

We need to find the number of textbooks of each type that were sold.

Let's call C the number of Chemistry books and P the number of Physics books that were sold.

Since the store sold a combined total of 252, we have:

$C+P=252$

Also, the number of chemistry textbooks sold was 78 more than the number of physics textbooks sold:

$C=78+P$

Then, in order to find the value of P, we can replace C with 78+P in the first equation. We obtain:

$\begin{gathered} 78+P+P=252 \\ \\ 78+2P=252 \\ \\ 78+2P-78=252-78 \\ \\ 2P=174 \\ \\ \frac{2P}{2}=\frac{174}{2} \\ \\ P=87 \end{gathered}$

Now, we can use the above result to find C:

$\begin{gathered} C=78+87 \\ \\ C=165 \end{gathered}$

Therefore, the answers are:

• Number of chemistry textbooks sold:, ,165

• Number of physics textbooks sold:, ,87