Paul ordered seven lemonade ice-blocks and 12 chocolate-coated ice-creams, which would have cost

him $38.60. However, he changed his order to eight chocolate-coated ice-creams and 11 lemonade

ice-blocks, saving $4. Develop a mathematical model to calculate the individual price of a lemonade

ice-block and a chocolate-coated ice-cream.

Evaluate the reasonableness of your solution.