Mathematics Mcqs

A. 26
B. 28
C. 30
D. 32
Explanation:
Let A = Set of students who fail in English
B = Set of students who fair in mathematics
Then , n(A) = 50, n(B) = 30 and n(A∩ B) = 12.
n(AUB) = n(A) + n(B)- n(A∩B) = (50 + 30 -12) = 68
Number of students who fail in one or both the students = 68
Number of those who pass in both = (100 – 68) = 32

A. 13 %
B. 11 1/9 %
C. 11.25 %
D. 12 1/9 %
Explanation:
Let the C.P of the article be Rs 1 per gram
C.P of 900gm = Rs 900,
S.P of 1000gm = Rs 1000
Gain % = (100/900 × 100)% = 100/9 % = 11 1/9 %

A. 10 litres
B. 15 litres
C. 66 2/3 litres
D. 20 litres
Explanation:
Let the capacity of the bucket be x liters
(80% of x) – (200/3% of x) = 2
=> (80/100 × x) – (200/300 × x) = 2
=> 4x/5 – 2x/3 = 2
=> (12x -10x) = 30
=> 2x = 30
=> X = 15 Litres

A. 18 3/4 %
B. 20 %
C. 16 3/4 %
D. 19 %
Explanation:
Required % = (9/48 × 100)% = 75/4 % = 18 ¾ %

A. does not change
B. decreased by 1 %
C. increased by 1 %
D. None of these
Explanation:
Let the given number be x
Increased Number = (110% of x)
= (110/100 × x) = (11x/10)
Finally reduced number = (90 % of 11x/10)
= (90/100 × 11x/10) = 99x/100
Decrease = (x – 99x/100) = x/100
Decrease % = (x/100 × 1/x × 100)% = 1 %

A. 2:5
B. 4:5
C. 6:7
D. 3:5
Explanation:
Let the third number be x.
Then 1st number = 120% of x = (120/100 × x) = 6x/5
2nd number = 150 % of x = (150/100 × x) = 3x/2
Ratio of these numbers = 6x/5 : 3x/2 = 12: 15 = 4 : 5

A. 25 %
B. 55%
C. 40.5 %
D. 56.25 %
Explanation:
Let the side of the square be x units.
Then it’s area = x2 sq. Units
Side of new square = 125 % of x = (125/100 × x)units = 5x/4 units
New area = (5x/4 × 5x/4)sq.units = 25×2/16 Sq.units
Increase in area = (25×2/16 – x2) = 9×2/16 Sq.Units
Increase % = (9×2/16 × 1/x2 × 100)%
= 225/4 % = 56.25 %

A. 65 %
B. 70 %
C. 80 %
D. 60%
Explanation:
Total Area of the Paper = (30 × 15) Sq.cm = 450 Sq.cm
Area Used = [(30-5)×(15-2.5) ]Sq.cm
= (25 × 12.5) Sq.cm = (25 x 25/2) Sq.cm = 625/2 cm2
Percentage are Used by = (625/2× 1/450×100) %
= 69.4 % = 70 % nearly

A. neither increased nor decreased
B. increased by 1 %
C. decreased by 1 %
D. decreased by 10 %
Explanation:
Let original length = l units and original breadth = b units
Then original Area = lb sq. Units
New length = (110/100 l) units = (11 l)/10 units
New breadth = (90/100 b) units = (9 l)/10 units
New area = (11l/10 × 9b/10) sq. Units = 99lb/100 sq. units
Decrease in area = (lb- 99lb/100)sq units = lb/100 sq. units
Decrease in area = (lb/100 × 1/lb ×100) % = 1 %
Decrease by = 1 %