If A : B = 1 : 3, B : C = 5 : 7, C : D = 9 : 7, then A : B : C : D = ?
If A : B = 1 : 3, B : C = 5 : 7, C : D = 9 : 7, then A : B : C : D = ?
If A : B = 1 : 3, B : C = 5 : 7, C : D = 9 : 7, then A : B : C : D = ?
Nithin ? undefined
Correct answer is: 15 : 45 : 63 : 49
Explanation:
A : B = 1 : 3 = 15 : 45
B : C = 5 : 7 = (5 × 9) : (7 × 9) = 45 : 63
C : D = 9 : 7 = (9 × 7) : (7 × 7) = 63 : 49
∴ A : B : C : D = 15 : 45 : 63 : 49
Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:
Nithin ? undefined
Correct answer is: 3 : 2
Explanation:
\(\eqalign{ & {\text{Let}}\,{\text{the}}\,{\text{speeds}}\,{\text{of}}\,{\text{the}}\,{\text{two}}\,{\text{trains}}\,{\text{be}}\,x\,{\text{m/sec}} \cr & {\text{and}}\,y\,{\text{m/sec}}\,{\text{respectively}}. \cr & {\text{Then,}}\,{\text{length}}\,{\text{of}}\,{\text{the}}\,{\text{first}}\,{\text{train}} = 27x\,{\text{metres}}, \cr & {\text{and}}\,{\text{length}}\,{\text{of}}\,{\text{the}}\,{\text{second}}\,{\text{train}} = 17y\,{\text{metres}}. \cr & \therefore \frac{{27x + 17y}}{{x + y}} = 23 \cr & \Rightarrow 27x + 17y = 23x + 23y \cr & \Rightarrow 4x = 6y \cr & \Rightarrow \frac{x}{y} = \frac{3}{2} \cr} \)
The average score of a class of boys and girls in an examination is A. The ratio of boys and girls in the class is 3 : 1. If the average score of the boys is A + 1, the average score of the girls is-
Nithin ? undefined
Correct answer is: A - 3
Explanation:
Let the number of boys and girls in the class be 3x and x respectively.
Let the average score of the girls be y.
Then,
⇒ 3x (A + 1) + xy = (3x + x) A
⇒ 3 (A + 1) y = 4A
⇒ y = A - 3
The ratio of the number of students studying in school A, B and C is 5 : 6 : 8. lf the number of students in each of the schools is increased by 30%, 25% and 25% respectively, what will be the new ratio of the students in schools A, B and C?
Nithin ? undefined
Correct answer is: 13 : 15 : 20
Explanation:
Number of students :
A => 5x
B => 6x
C=> 8x
Therefore, Required ratio\(= \frac{5x \times 130}{100}:\frac{6x \times 125}{100}:\frac{8x \times 125}{100}\)
= 650 : 750 : 1000
= 13 : 15 : 20
In a ratio which is equal to 5 : 8. If the antecedent is 40 then consequent is ?
Nithin ? undefined
Correct answer is: 64
Explanation:
∵ 5 : 8 : : 40 : N
N = \(\frac{40 \times 8}{5}\)
∴ consequent N = 64
The difference between the present age of Anil and Sudhii is 6 years. The ratio between their age after 4 years will be 3 : 4. What can be the present age of Sudhir?
Nithin ? undefined
Correct answer is: 20 years
Explanation:
After four years.
Anil a = 3x years
Sudhir = 4x years
In the present,
4x - 4 - 3x + 4 = 6 => x = 6
Therefore, Sudhir's present age = 4x - 4 = \(4 \times 6 - 4\)= 20 years
The price of sugar is increased by 20%. If the expenditure is not allowed to increased. Then ratio between the reduction in consumption and the original consumption ?
Nithin ? undefined
Correct answer is: 1 : 6
Explanation:
Reduction in consumption = \(\frac{20}{120} \times 100 \text{%} = \frac{50}{3}\text{%}\)
∴ Reduction in consumption /Original consumption = \(\frac{\frac{50}{3} }{100} = \frac{1}{6} = 1 : 6\)