Plugging in can really save time here if you pick numbers.
I had to start over 5 times before i got it right!
It was quite confusing.
For the first 1/4 Kg: T Cents.
For the next 3: 3*0.2T Cents = 0.6 Cents.
(3 * 1/4 Kg to complete a whole 1Kg.)
We know that the first 1Kg, will cost 1.6T Cents.
What's left is (P-1) Kg. Which contains 4*(p-1) quarters of a Kg.
So the answer is : 1.6T + (P-1)*4*0.2T
Work with that and you get the same equation as in E.
yeah, algebraically there are so many ways to work this out, and you might not get the same answer as one of the choices. Dookie's way works great - the way I did it was also right but did not produce any of the answers. I think plugging in worked just fine here.
But what threw me off was the phrase "Or any fraction thereof". Because of that, I assumed this didn't have to be whole number kg's, because a whole number would always have an exact amount of .25kgs. I spent a while trying to figure that out before I realized it said that P was an integer. That was a little weird....