Mr lol bought x oranges for $30 and sold them at a profit of 5cents per orange. Write down the (i)cost price of an orange.

(ii)the selling price of an orange

When he had sold all except 20 of the oranges, he found he had received $28.
(iii) form an equation in x and show that it simplifies to xsquare + 20x -12000= 0

1. Cost = $30/X per orange.

2. Selling Price = (30/X+0.05)per orange.

3. (30/X + 0.05)(X - 20) = 28,
Multiply the 2 binomials and get:
30 - 600/X + 0.05X - 1 = 28,
Multiply both sides by X:
30X - 600 + 0.05X^2 - X = 28X,
0.05X^2 + 29X - 600 = 28X,
0.05X^2 + 29X - 28X - 600 = 0,
0.05X^2 + X - 600 = 0,
Multiply both sides by 20:
X^2 + 20X - 12000 = 0.

But your solution of this problem doesn't show the stuff that any real businessman would want to know. How many oranges? What is my unit cost in actual cents not formula? When will I be in profit? etc

Thanks a lot Henry! Your working is right!

Btw, thank too Raymond for helping me out, I appreciate it a lot (:

Appreciate both of you who help me! Thanks!!!!!

Btw Henry, why multiply by 20 in the end? Is it because he had sold all except 20 of the oranges?

(i) To find the cost price of an orange, we can divide the total amount spent on oranges by the number of oranges bought. In this case, Mr. Lol bought x oranges for $30. So the cost price of an orange can be calculated as follows:

Cost price of an orange = Total amount spent / Number of oranges
= $30 / x

(ii) To find the selling price of an orange, we need to add the profit per orange to the cost price. Here, the profit is given as 5 cents (which is equivalent to $0.05).

Selling price of an orange = Cost price + Profit
= $30 / x + $0.05

(iii) When Mr. Lol sold all the oranges except 20, he received $28. Let's assume the selling price of each orange is y.

Total selling price of x-20 oranges = y(x-20)

As it is given that the total selling price of x-20 oranges is $28, we can write:

y(x-20) = $28

Substituting the expression for selling price (y) from part (ii), we get:

($30 / x + $0.05)(x-20) = $28

To simplify further, let's remove the dollar signs:

(30/x + 0.05)(x-20) = 28

Next, we can multiply the expression out:

30(x-20)/x + 0.05(x-20) = 28

Expanding both terms and combining like terms, we get:

30x / x - 600/x + 0.05x - 1 = 28

Simplifying the first term by canceling out x, we have:

30 - 600/x + 0.05x - 1 = 28

Now, let's combine like terms:

- 600/x + 0.05x = 28 - 30 + 1

Simplifying further, we get:

- 600/x + 0.05x = -1

Multiplying through by x to remove the denominator, we have:

- 600 + 0.05x² = -x

Rearranging the equation, we get:

0.05x² + x - 600 = 0

Therefore, the equation simplifies to xsquare + 20x - 12000 = 0.