Sarah took the advertising department from her company on a round trip to meet with a potential client. Including Sarah a total of 11 people took the trip. She was able to purchase coach tickets for $240 and first class tickets for $1080. She used her total budget for airfare for the trip, which was $4320. How many first class tickets did she buy? How many coach tickets did she buy?

You can set up a system of equations for this problem. Let x = number of coach tickets and y = number of first-class tickets. Then:

330x + 1220y = 12730    (cost of coach tickets plus cost of first-class tickets is total budget)

x + y = 17    (number of coach tickets plus the number of first-class tickets is the total number of people)

Solve the second equation for y to get y = 17 - x, then plug that into the first equation and solve for x:

330x + 1220(17 - x) = 12730

330x + 20740 - 1220x = 12730

-890x + 20740 = 12730

-890x = -8010

x = 9

Sarah bought x = 9 coach tickets. Put that into the second equation and solve for y:

9 + y = 17

y = 8

Sarah bought y = 8 first-class tickets.

Hope this helps!! :D

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.