If you give me answers i can give you the right one
Answer: the old price for 1 liter is $0.3
Step-by-step explanation:
Let x represent the old price for 1 liter of petrol.
Last week a man bought 20 liters at the old price. This means that the total amount that the man paid for 20 liters is 20x.
The cost of petrol rises by 2 cents a liter. This means that the new price per liter is x + 2/100 = x + 0.02
This week he bought 10 liters at the new price. This means that the total amount that the man paid for 10 liters is
10(x + 0.02)
= 10x + 0.2
Altogether, the petrol costs $9.20. This means that
20x + 10x + 0.2 = 9.2
30x + 0.2 = 9.2
30x = 9.2 - 0.2
30x = 9
x = 9/30
x = 0.3
First find the characteristic solution. The characteristic equation is

which as one root at

of multiplicity 2. This means the characteristic solution for this ODE is

For the nonhomogeneous part, you can try a particular solution of the form

which has derivatives


Substituting into the ODE, the left hand side reduces significantly to

and it follows that

Therefore the particular solution is

and so the general solution is the sum of the characteristic and particular solutions,

1245 divide by 2 is 622.5 I did this on a calculator.
The answer would be 370 2/22.
This is also equivalent to 370 1/11.
Hope this helps. If you have any questions, place it in the comment section below.