Answer:
5 seats
Step-by-step explanation:
if I'm getting the right idea, the seats are NOT enough
since the number of arrangement of 10 people in a row is
10! = 3628800 which is a lot larger than 30240.
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Let number of seats be
10PX = 30240
= 30240
(10-X)! = 
(10-X)! = 120
(10-X)! = 5!
10-X = 5
X = 5
Food = 1/4
gasoline = 3/5
Total = 1/4 + 3/5 = 17/20
17/20 = 272
1/20 = 272 ÷ 17 = 16
20/20 = 16 x 20 = $320
I think the teacher would probably pick two boys and one girl