1. Fresh fruit contains 68 % water and dry fruit contains 20 % water. How much dry fruit can be obtained from 100 kg of fresh fruits?
A. 32 kg
B. 40 kg
C. 52 kg
D. 80 kg
Answer - Option B
Explanation -
Quantity of water in 100kg of fresh fruits = ([latex]\frac {68} {100}[/latex] x 100) )kg
Quantity of pulp in it = (100 - 68)kg = 32 kg
Let the dry fruit be x kg
Water in it = ([latex]\frac {20} {100}[/latex] x 100) )kg = [latex]\frac {x} {5}[/latex] kg
Quantity of pulp in it = (x - [latex]\frac {x} {5}[/latex])kg = [latex]\frac {4x} {5}[/latex] kg
Therefore, [latex]\frac {4x} {5}[/latex] kg = 32 => x = [latex]\frac {160} {4}[/latex] = 40 kg
2. Fresh grapes contain 80 % water dry grapes contain 10 % water. If the weight of dry grapes is 250 kg. What was its total weight when it was fresh?
A. 1000 kg
B. 1100 kg
C. 1125 kg
D. 1125 kg
Answer - Option C
Explanation -
Let the weight of fresh grapes be x kg
Quantity of water in it = ([latex]\frac {80} {100}[/latex] × x)kg = [latex]\frac {4x} {5}[/latex] kg
Quantity of pulp in it = (x - [latex]\frac {4x} {5}[/latex] )kg = [latex]\frac {x} {5}[/latex] kg
Quantity of water in 250 kg dry grapes
= ([latex]\frac {10} {100}[/latex] × 250)kg = 25kg
Quantity of pulp in it = (250 - 25)kg = 225 kg
Therefore, [latex]\frac {x} {5}[/latex] = 225
=> x = 1125
3. The quality of water that should be added to reduce 9 ml. Lotion containing 50 % alcohol to a lotion containing 30 % alcohol is
A. 3 ml
B. 4 ml
C. 5 ml
D. 6 ml
Answer - Option D
Explanation -
Alcohol in 9 ml lotion = ([latex]\frac {50} {100}[/latex] × 9)ml = 4.5 ml
Water in it = (9 – 4.5)ml = 4.5 ml
Let x ml of water be added to it, then [latex]\frac {4.5} {9+x}[/latex] × 100 = 30
=> [latex]\frac {4.5} {9+x}[/latex] = [latex]\frac {30} {100}[/latex] = [latex]\frac {3} {10}[/latex]
=> 3(9+x) = 45 => 27 + 3x = 45
=> 3x = 18
=> x = 6
Water to be added = 6 ml
4. In a school, 40 % of the students play football and 50 % play cricket. If 18 % of the students play neither football nor cricket, the percentage of students playing both is
A. 40 %
B. 32 %
C. 22 %
D. 8 %
Answer - Option D
Explanation -
Let A = set of students who play football and
B = set of students play cricket.
Then n(A) = 40, n (B) = 50 and
n(A U B) = (100 - 18) = 82
n(A U B) = n(A) + n(B) – n(A ∩ B)
n(A∩B) = n(A) + n(B) – n(AUB) = (40 + 50 -82) = 8
Percentage of the students who play both = 8%
5. If the price of the eraser is reduced by 25% a person buy 2 more erasers for a rupee. How many erasers available for a rupee?
Answer - Option B
Explanation -
Let n erasers be available for a rupee
Reduced Price = ([latex]\frac {75} {100}[/latex] × 1) = [latex]\frac {3} {4}[/latex]
[latex]\frac {3} {4}[/latex] rupee fetch n erasers = 1 Rupee will fetch (n × [latex]\frac {4} {3}[/latex]) erasers
Therefore, [latex]\frac {4n} {3}[/latex] = n +2 => 4n = 3n +6 => n = 6