Mensuration:
1. The breadth of a rectangle is equal to the diameter of a circle. The circumference of a circle is equal to the perimeter of a square of side 33m. What is the length of a rectangle. If the area of a rectangle is 756[latex] m^2 [/latex]?
A. 18m
B. 19m
C. 20m
D. 17m
E. 16m
Answer: Option A
Solution: According to the question,
Perimeter of a square = 4 × side
Perimeter of a square = 4 × 33 = 132m
Circumference of a circle 2πr
132 = 2 [latex] \frac{22} {7}[/latex] × r
r = 21m
Diameter of a circle = 2r
Diameter of a circle = 2 × 21 = 42m
Breadth of a rectangle = 42m
Area of a rectangle = 756 [latex] m^2 [/latex]
Area of a rectangle = Length of a rectangle × Breadth of a rectangle
Length of a rectangle = [latex] \frac{756} {42}[/latex] = 18m
Compound Interest:
2. What will be the compound interest on a sum of Rs. 44,375 at compound interest compounded annually at 12% per annum in two years?
A. Rs.11,288
B. Rs.11,290
C. Rs.11,289
D. Rs.11,287
E. Rs.11,291
Answer: Option C
Solution: According to the question,
P = Rs.44,375
r = 12%
t = 2 years
C.I = P({1 + [latex] \frac{r} {100})^t[/latex] - 1}
C.I = 44375{(1 + [latex] \frac{12} {100})^2[/latex]- 1}
C.I = 44375{( [latex] \frac{25 + 3} {25})^2[/latex]- 1}
C.I = 44375{[latex] \frac{784 } {625}[/latex] - 1}
C.I = 44375{[latex] \frac{784 - 625} {625}[/latex]}
C.I = 44375 x [latex] \frac{159} {625}[/latex]
C.I = 71 x 159 = Rs.11,289
Time and work:
3. 14 girls and 10 boys can do a piece of work in 5 days while 14 girls and 6 boys can do the same piece of work in 6 days. In how many days can 19 girls and 16 boys do the same piece of work?
A. 3[latex] \frac{6} {7}[/latex] days
B. 3[latex] \frac{5} {7}[/latex] days
C. 3[latex] \frac{2} {7}[/latex] days
D. 3[latex] \frac{3} {7}[/latex] days
E. 3[latex] \frac{4} {7}[/latex] days
Answer: Option D
Solution: 14 girls and 10 boys 1 day work
14 girls and 6 boys 1 day work
According to the question,
(14 girls + 10 boys) × 5 ≡ (14 girls + 6 boys) × 6
(70 girls + 50 boys) × 5 ≡ (84 girls + 36 boys) × 6
14 boys ≡ 14 girls
1 boy ≡ 1 girl
(19 girls + 50 boys) ≡ (19 girls + 16 boys) = 35 boys
M
1 D
1 = M
2 D
2
24 x 5 = 35 D
2
D
2 = [latex] \frac{5 × 24} {35}[/latex]
D
2 = 3[latex] \frac{3} {7}[/latex]
Percentage:
4. If the numerator of a fraction is increased by and denominator is also increased by then the value of fraction is [latex] \frac{4} {7}[/latex]. The original fraction is:
A. [latex] \frac{29} {50}[/latex]
B. [latex] \frac{30} {55}[/latex]
C. [latex] \frac{34} {55}[/latex]
D. [latex] \frac{31} {55}[/latex]
E. [latex] \frac{32} {55}[/latex]
Answer: Option A
Solution: According to the question,
Let the original fraction be [latex] \frac{100 x} {100 y}[/latex] then,
([latex] \frac{100 + 450} {100 + 300}[/latex])[latex] \frac{x} {y}[/latex] = [latex] \frac{4} {5}[/latex]
The original fraction
([latex] \frac{550} {400}[/latex])[latex] \frac{x} {y}[/latex] = [latex] \frac{4} {5}[/latex]
([latex] \frac{x} {y}[/latex]) = [latex] \frac{4 × 8} {11 × 5 }[/latex]
([latex] \frac{x} {y}[/latex]) = [latex] \frac{32} {55}[/latex]
The original fraction = [latex] \frac{32} {55}[/latex]
Ratio and Proportion:
5. In a college the students in Math and Hindi classes are in the ratio 17:19. When 12 more students join Hindi class the ratio becomes 17:21. How many students are there in the Hindi class?
A. 115
B. 110
C. 112
D. 114
E. 113
Answer: Option D
Solution: Let the number of students in Math and Hindi be , then According to the question,
([latex] \frac{17 x} {19 x + 12}[/latex]) = [latex] \frac{17} {21}[/latex]
357x = 323x + 204
357x - 323x - 204
34x = 204
x = 6
Number of students in Hindi class = 19x = 19 × 6 =114
Pipes and Cistern: