Answer: 4,230 miles
Step-by-step explanation:
Let x = Number of miles each jet travel so they both have the same amount of fuel remaining.
Fuel left = (Initial fuel)- (Fuel burns per mile)(Number of miles)
For standard airline,
Fuel left = 25812 - 4.2 x
For Jumbo airline,
Fuel left = 31311 - 5.5 x
According to the question,
[tex]25812 - 4.2 x=31311 - 5.5 x\\\\\Rightarrow\ 5.5x-4.2x=31311-25812\\\\\Rightarrow\ 1.3x= 5499\\\\\Rightarrow\ x=\dfrac{5499}{1.3}\\\\\Rightarrow\ x=4230[/tex]
Hence, Each jet must travel 4,230 miles so they both have the same amount of fuel remaining.