Slimination
the teacher probably wants you to eliminate the x terms since there are an equal number of them
so multiply first equation by -1
-6x+3y=-30
add to second equation
6x-6x+3y+y=18-30
0x+4y=-12
4y=-12
divide by 4
y=-3
subsitute
6x+-3=18
add 3
6x=21
divide both sides by 6
x=21/6=7/2
x=7/2
y=-3
Jill will make less money if they work for 4 hours
Answer is 120 in^3
Reason
Cone volume is 1/3 BH
(or 1/3 volume of a cylinder)
1/3 x 36 x 10
Answer = 120
If y/x does not always equal the same