conditional average

R.K wrote:Babar spends equal amount in buying two types of oranges at the rate of 5 oranges for a rupee and 10 oranges for 3 rupees. the average cost of the oranges will be...

Let us say that Babar spent 3 Rupees to buy each type of Orange.
In 3 Rupees, he would buy 5*3 = 15 oranges of Type1 and 10 oranges of Type2.

Average
= Total money spent/Number of oranges
= (3 + 3)/(15 + 10)
= [spoiler]6/25 Rupees[/spoiler]
or
(6/25)*100 paise
= 24 paise

GMAT uses US currency terminology in its problems.
What's the source?

no but the answer is 25 paisa..

R.K wrote:no but the answer is 25 paisa..

25 paisa CANNOT be the answer.

Type1 oranges cost 100/5 = 20 paisa per orange, and
Type2 oranges cost 300/10 = 30 paisa per orange.

25 paisa, which is the mean of 20 paisa and 30 paisa, would be the answer only when he buys same quantities of each orange.
But, he cannot buy same quantities of each orange because he is spending equal amount of money for buying each type of oranges and the cost of one orange of each type is different.

Please check the answer again.

thank u so much........ [/img]

R.K wrote:Babar spends equal amount in buying two types of oranges at the rate of 5 oranges for a rupee and 10 oranges for 3 rupees. the average cost of the oranges will be...

Type 1

5 oranges = Rupee 1

Type 2

10 oranges for 3 rupees


Now we consider type 1 ...

5 oranges cost rupee 1 , so 10 oranges will cost Re 2

Now we have 2 buying costs -

Type 1 - 10 oranges for 2 rupees

Type 2 - 10 oranges for 3 rupees

_____________________________________

Add - 20 oranges costs Rs 5

So , 4 Orange costs Rs 1

Or , 1 Orange can be bought for 1/4 Rupee..

Abhishek009 wrote:

R.K wrote:Babar spends equal amount in buying two types of oranges at the rate of 5 oranges for a rupee and 10 oranges for 3 rupees. the average cost of the oranges will be...

Type 1

5 oranges = Rupee 1

Type 2

10 oranges for 3 rupees


Now we consider type 1 ...

5 oranges cost rupee 1 , so 10 oranges will cost Re 2

Now we have 2 buying costs -

Type 1 - 10 oranges for 2 rupees

Type 2 - 10 oranges for 3 rupees

_____________________________________

Add - 20 oranges costs Rs 5

So , 4 Orange costs Rs 1

Or , 1 Orange can be bought for 1/4 Rupee..

Hi Abhishek,

If you read the problem again, you will realise that you've made a mistake.

Babar spends an equal amount of money to purchase each type of orange. In your example, he spends 2 rupees for Type1 while 3 rupees for Type2.

If you correct that, I'm sure you'll get the correct answer, which is: 24 paise

Does that make sense?