Any

in this set will be real numbers that are both less than

and greater than

. But that's not possible, so this set is empty.
Answer: Satisfied for n=1, n=k and n=k+1
Step-by-step explanation:
The induction procedure involves two steps
First is
Basic Step
Here we consider that for the value n=1, there is one car and it will always make the full circle.
Induction Step
Since basic step is satisfied for n=1
Now we do it for n=k+1
Now according to the statement a car makes full circle by taking gas from other cars as it passes them. This means there are cars that are there to provide fuel to the car. So we have a car that can be eliminated i.e. it gives it fuels to other car to make full circle so it is always there.
Now ,go through the statement again that the original car gets past the other car and take the gas from it to eliminate it. So now cars remain k instead of k+1 as it's fuel has been taken. Now the car that has taken the fuel can make the full circle. The gas is enough to make a circle now.
So by induction we can find a car that satisfies k+1 induction so for k number of cars, we can also find a car that makes a full circle.
In this type of calculations, we decompose 13 by checking the lowest powers of the base, that is 40. for example we check 40^2, or 40^3 and compare it to 85
Notice
40*40*40=64,000
so we check how many time does 85 fit into 64,000:
64,000/85=752.94
85*753=64,005; 64000-64,005=-5
this means that

thus

Answer: 10 (mod85)
Remark, the set of all solutions is:
{......-75, 10, 95, .....}, that is 85k +10
3 multiplied by ten to the second power