I am trying to help my 15 year old with her Critical Thinking homework. She has the entire worksheet finished except for this one problem. I want to help her but I don't even know how to start with this one. I would really like to learn how to solve it. Here is the math problem...
Photographs of students are taken and offered for sale in various packages.
2 large and 3 small: \\\$8.00
3 large and 3 small: \\\$9.00
4 large and 2 small: \\\$11.00
These prices include the same amount for postage and packaging.
What is the cost of postage and packaging included in these prices?
Please help me understand how to solve this.
Thank you.
The prices don’t make sense but here is an attempt to make sense of them. $$2L+3S+P=\$8\land 3L+3S+P=\$9 \implies L=$1$$ By logic, then $$ 4L+3S+P=\$10\quad\text{ but}\quad 4L+2S+P=\$11\implies S=-\$1$$ Back to the original $$2L+3S+P=2(\$1)+3(-\$1)+P=-\$1+P=\$8\implies P=\$9$$ $$3L+3S+P=3(\$1)+3(-\$1)+P=\$0+P=\$8\implies P=\$9$$ $$4L+2S+P=4(\$1)+2(-\$1)+P=\$2+P=\$11\implies P=\$9$$