Aptitude - Alligation or Mixture - Discussion

Discussion Forum : Alligation or Mixture - General Questions (Q.No. 7)
7.
How many kilogram of sugar costing Rs. 9 per kg must be mixed with 27 kg of sugar costing Rs. 7 per kg so that there may be a gain of 10% by selling the mixture at Rs. 9.24 per kg?
36 kg
42 kg
54 kg
63 kg
Answer: Option
Explanation:

S.P. of 1 kg of mixture = Rs. 9.24, Gain 10%.

C.P. of 1 kg of mixture = Rs. 100 x 9.24 = Rs. 8.40
110

By the rule of allilation, we have:

C.P. of 1 kg sugar of 1st kind Cost of 1 kg sugar of 2nd kind
Rs. 9 Mean Price
Rs. 8.40
Rs. 7
1.40 0.60

Ratio of quantities of 1st and 2nd kind = 14 : 6 = 7 : 3.

Let x kg of sugar of 1st be mixed with 27 kg of 2nd kind.

Then, 7 : 3 = x : 27

x = 7 x 27 = 63 kg.
3

Discussion:
40 comments Page 4 of 4.

P.s.manikanta said:   1 decade ago
Observe the allegation method which is given as solution. They are mixed in the ratio 1.40:0.60 =14:60. This ratio always remains constant in allegation. They have already given 27kg for sugar costing 7rs/- per kg. The question asked is how many (?) kgs of sugar costing 9rs/- per kg should be mixed. So equate the ratio of weights.

Vijay said:   1 decade ago
Solve in another method: Amount of 1st kind 'x'and its cost Rs.9/kg and amount of 2nd kind is 27kg and its cost is 7/kg.
c.p of mixture=(9x+(27*7))
s.p of mixture=9.24*(27+x)
Profit=(s.p-c.p)/c.p=10/100
Then we get x value.

Ram said:   1 decade ago
How the 14:6 come can any one explain ?

May said:   1 decade ago
Can explain me for ratio ??

Sri said:   1 decade ago
Mean price?

Raji said:   1 decade ago
Sorry I cant understood what amit said. Kindly explain it.

Amit said:   1 decade ago
its simple

(quantity of cheaper/quantity of dearer=cp of dearer-mean price)/(cp of cheaper/cp of mean).

So 27/x=0.6/1.4
x=63.....
So simple

Rahul said:   1 decade ago
This is same as last problem. Here goes:
Selling price is 9.24 and profit is 10% so:
Cost price + Profit = Selling Price
Let cost price be equal to x:
x + 0.1x = 9.24
1.1x = 9.24
x = 924/11 which is 8.4

Then you do alligation which is shown in the explanation to bring the ratio of Rs. 9 sugar to Rs. 7 sugar down to 7:3

So Amount of Rs. 9 sugar (lets call it A) is related to amount of Rs. 7 sugar by the following formula:
A/27 = 7/3 (since we found out the ratio they are in)
Now solve for A by cross multiplying:
3A = 27 x 7
A = (27 x 7)/3 [27/3 reduces down to 9) = 9 x 7 = 63kg

Suhani said:   1 decade ago
Hi,

How the C. P is calculated?

Sivaram said:   1 decade ago
Hi Friends,

I can't understand why we take x to b mixed with 27kg of sugar (last step).

Please some one help me out. Thank you.


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