Latest TCS Aptitude Question SOLUTION: How many litres of concentrated 90% acid need to be mixed with 75% solution of concentrated acid to get a 3o litre soluton of concentrated acid

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How many litres of concentrated 90% acid need to be mixed with 75% solution of concentrated acid to get a 3o litre soluton of concentrated acid

Asked In TCS prashant (11 years ago)

Unsolved Read Solution (7)

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Honey  (11 years ago)

how can we find the volume of solution when we don't noe the volume of either solvant..

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Isha  (11 years ago)

Funny answer,
If 78 ltrs of one mixture is added , how will you get only 30 ltr of total mixture of unknown coceerntration ?

Is this solution Helpfull? Yes (3) | No (1)  

ayush gupta  (11 years ago)

78 is answer

Is this solution Helpfull? Yes (1) | No (8)  

rajesh chaparala  (11 years ago)

rajesh.chaparala@gmail.com

Is this solution Helpfull? Yes (1) | No (1)  

hussainsheriff  (11 years ago)

7.5 liter

Is this solution Helpfull? Yes | No (1)  

abhishek bhiwaniwala  (10 years ago)

RATIO 90%:75%=5:2 can be obained using alligations
thus,150/7 of 90% needs to be mixed with 60/7 of 75%

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Deepannita Pal  (9 years ago)

Answer: Op 3: 6L.
Solution:
It is a linear problem of 2 variables. suppose we mix x litres of 90% concentrated acid with y litres of 75% concentrated acid. Total we get 30 litres. Therefore,
x + y = 30 ------------ equation (1)
The resulting mixture has 78% concentrated acid, therefore, 78%*30 = 23.4 litres of acid.
First solution has 90% acid, second has 75% acid, therefore,
0.9x + 0.75y = 78%*30 = 23.4 ------------ equation (2)
0.9x + 0.9 y = 0.9*30 = 27 ---------------- modified equation (1)
subtracting equation 2 from equation 1,
0.15y = 3.6. it follows that y = 24, i.e., 3.6/0.15
Also x + y = 30, therefore x = 30 - y = 30 - 24 = 6.

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