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50697.One type of liquid contains 25 % of benzene, the other contains 30% of benzene. A can is filled with 6 parts of the first liquid and 4 parts of the second liquid. Find the percentage of benzene in the new mixture.
28 %
25 %
30 %
27%
Explanation:

Let the percentage of benzene =X
(30 - X)/(X- 25) = 6/4 = 3/2
=> 5X = 135 or
X = 27 so,
required percentage of benzene = 27 %

50698.A jar contains a mixture of two liquids Acid( nitric acid) and Base(ammonium chloride) in the ratio 4 : 1. When 10 litres of the mixture is taken out and 10 litres of liquid Base is poured into the jar, the ratio becomes 2 : 3. How many litres of liquid Acid was contained in the jar?
14 lts
18 lts
20 lts
16 lts
Explanation:
%age of liquid Base in the original mixture =1/5 x 100 = 20% In the final mixture % of the liquid Base = 3/5 x 100 = 60% Now using the rule of allegation Hence reduced quantity of the first mixture and the quantity of mixture B which is to be added are the same. Total mixture = 10 + 10 = 20 liters and quantity of liquid A = 20/5 x 4 = 16 lts
50699.A housewife has 11 litre of solution that contains sodium carbonate solution and benzene solution in the ratio 3 : 1. She adds 250 ml of 3 : 2 solution of sodium carbonate and benzene solution to it and then uses 250 ml of the combined mixture to make strong organic solution How much of pure sodium carbonate solution is she left with?
1000 ml
912.5 ml
750 ml
720 ml
Explanation:

ln a mixture of 1,000 ml sodium carbonate : benzene solution = 3 : 1.
Hence, sodium carbonate: 750 ml benzene solution 250 ml
A 250 ml of 3 : 2 solution contains 150 ml sodium carbonate solution and l00ml benzene solution.
Total sodium carbonate solution = 900 ml, total benzene solution = 350 ml
After using 250 ml to make strong organic solution , sodium carbonate solution used
= 250/1250 x 900 = 180 ml
pure sodium carbonate solution left = 900 -180 =720ml

50700.The mean proportional between 45 and a certain number is three times the mean proportional between 5 and 22. The number is ?
24
49
22
9
Explanation:

If X be the required number, then
(45 x X)1/2 = 3 x (5 x 22)1/2
45X = 9 x 110
X = 22

50701.A and B are two alloys of argentum and brass prepared by mixing metals in proportions 7 : 2 and 7 : 11 respectively. If equal quantities of the two alloys are melted to form a third alloy C, the proportion of argentum and brass in C will be ?
5 : 9
5 : 7
7:5
9:5
Explanation:

The first alloy is prepared by mixing metals in proportions 7 : 2,
Then the weight of the first alloy will be = 7x + 2x
Assume ’x’ = 1Kg
The weight of the first alloy will be 9kg
The second alloy is prepared by mixing metals in proportions 7 : 11,
The weight of the second alloy will be 18kg
If equal quantities of the two alloys are melted to form a third alloy,
Then 18Kg of first alloy should be used, then its ratio will become 14 : 4,
Now, the proportion of argentum and brass in third alloy = 7 + 14 : 11 + 4 = 21 : 15 = 7 : 5

50702.If x varies inversely as (y2 - 1) and is equal to 24 when y = 10, the value of x when y = 5 will be ?
100
101
99
None of these
Explanation:

Let X = K/(Y2 - 1).
Now 24 = K/(100 - 1)
Or K = 24 x 99.
X = K/(Y2 – 1)
When Y = 5, X = 24 × 99/(25 - 1 ) = 99

50703.The average salary of all the employees in a small organization is Rs 8,000. The average salary of 7 technicians is Rs 12,000 and the average salary of the rest is Rs 6,000. The total number of employees in the organisation is?
21
20
26
24
Explanation:

Let total number of employees be X.
Then, 8000 x X = 7 x 12000 + (X - 7) x 6000
X = 26.
Thus, the total number of employees in the organization is 26.

50704.Without any stoppage, a person travels a certain distance at an average speed of 42 km/h, and with stoppages he covers the same distance at an average speed of 28 km/h. How many minutes per hour does he stop?
14 minutes
15 minutes
28 minutes
None of these
Explanation:

Let the total distance to be covered is 48 kms.
Time taken to cover the distance without stoppage = 48/42 hrs = 2 hrs
Time taken to cover the distance with stoppage = 48/28 = 3 hrs.
Thus, he takes 60 minutes to cover the same distance with stoppage.
Therefore, in 1 hour he stops for 20 minutes.

50705.The average marks of a Suresh in 10 papers are 80. If the highest and the lowest scores are not considered, the average is 81. If his highest score is 92, find the lowest?
55
60
62
66
Explanation:

Total marks of 10 papers = 80 x 10 = 800
Total marks of 8 papers = 81 x 8 = 648
Total marks of two papers = (800 - 648) = 152
If highest total is 92, then the lowest total is
(152 - 92) = 60.

50706.Three maths classes: X, Y and Z take an algebra test. The average score of class X is 83. The average score of class Y is 76. The average score of class Z is 85. The average score of class X and Y is 79 and average score of class Y and Z is 81. What is the average score of classes X, Y, Z?
81.5
80.5
83
78
Explanation:

Let the number of students in classes X, Y and Z be A, B and C respectively.
Then, total score of X= 83A, total score of Y = 76B, total score of Z = 85C.
Also given that,
(83A + 76B) / (A + B) = 79
=>4A = 3B.

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