Multiply top equation by -2, then add equations so b drops out....solve for a...plug in a to get b
Since it’s $80 for 5 tickets, we divide 80/5 to get the price of one ticket, giving us
C = 16*n.
Plug in 5 for n and you’ll get 80
If Nate paints the wall in 4 hours, it means that he can paint 1/4 of the wall every hour.
Similarly, if Jill paints the wall in 7 hours, it means that he can paint 1/7 of the wall in one hour.
So, together, they paint the following fraction of the wall in one hour:
.
At this rate, they need 28/11 hours to paint the whole wall, in fact, after that amount of time they paint

i.e. the whole wall