pre-calculus, matrixes

Question

A local store is selling Halloween decorations, where there is a special sale on ghosts and pumpkins. If your neighbor were to buy 3 ghosts and a pumpkin, it would cost them $50, but if they were to buy a single ghost and 4 pumpkins, they would only spend $40. How much does each type of decoration cost?

Answer 1

3* ghost + pumpkin =50. eq1

ghost+ 4*pumpkin=40. eq2

3*eq2- eq1:

(4*3-1)* pumpkin =40*3-50. =>>11* pumpkin =70 =>> pumpkin=70/11=6.36

ghost=(50-70//11)/3=480/33=160/11= 14.54