Mrs, Singh purchased how many soft cover books?Mrs, Singh purchase how many hardcover books?

Explanation
In the question, we are given that Mrs.Singh purchased 31 softcover books and hardcover books. Let softcover books and the hardcover book be x and y respectively.
Therefore;
[tex]x+y=31----1[/tex]Also, each softcopy book costs $3.50 and hard copy books cost $14.50.
[tex]3.50x+14.50y=240.50---2[/tex]The next step is to solve the simultaneous equation.
[tex]x=31-y------3[/tex]Substitute equation iii into ii
[tex]\begin{gathered} 3.50(31-y)+14.50y=240.50 \\ 108.50-3.50y+14.50y=240.50 \\ 11y=240.50-108.50 \\ 11y=132 \\ \frac{11y}{11}=\frac{132}{11} \\ y=12 \end{gathered}[/tex]Next, we substitute the value of y in equation iii
[tex]\begin{gathered} x=31-12 \\ x=19 \end{gathered}[/tex]Therefore the answers are:
Soft cover books: 19 books
Hard coverbooks: 12 books