Mr.Wang spent $40 for 5 picture cards, 2 note book and a vase. The cost of 1 picture card and the vase was $16. The cost of 1 picture card and 1 note book was $10. What was the cost of the vase?
40= 5x+2y+z
16=x+z
10=x+y
solve for x
x=10-y
plug into 2nd equation
16=10-y+z
z=6+y
plug into first
5(10-y)+2y+6+y=40
y=8
plug in..
10=x+8
x=2
2+z=16
z (vase)=14