Dylan has x dimes and y nickels, having no less than 18 coins worth no more than $1.50 combined. A maximum of 6 of the coins are dimes and no more than 20 of the coins are nickels.

Question

Solve this system of inequalities graphically and determine one possible solution.

Answer 1

x + y >18

10x + 5y < 150

2x + y < 30

x < 6

y < 20

Graph those lines, shade in the right side of the line, and what you get seems to be a right triangle, 8 x 8 x 8sqr2, with vertices at (-2,20), (6,20) and (6,12)

in that area -2<x<6 and 12<y< 20

the line 2x+y<30 seems to be unnecessary, redundant.