ExamVeda
Login
Home
1
If A : B = $$\frac{1}{2}$$ : $$\frac{3}{8},$$  B : C = $$\frac{1}{3}$$ : $$\frac{5}{9}$$ and C : D = $$\frac{5}{6}$$ : $$\frac{3}{4},$$  then the ratio A : B : C : D is
Discuss
Answer & Solution
Answer: Option B
Solution:
$$\eqalign{ & {\text{A}}:{\text{B}} = \frac{1}{2}:\frac{3}{8} = 4:3, \cr & {\text{B}}:{\text{C}} = \frac{1}{3}:\frac{5}{9} = 3:5, \cr & {\text{C}}:{\text{D}} = \frac{5}{6}:\frac{3}{4} = 10:9 \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 5:\frac{9}{2}. \cr & \therefore {\text{A}}:{\text{B}}:{\text{C}}:{\text{D}} \cr & = 4:3:5:\frac{9}{2} \cr & = 8:6:10:9. \cr} $$
2
If p : q : r = 1 : 2 : 4, then $$\sqrt {5{p^2} + {q^2} + {r^2}} $$     is equal to =
Discuss
Answer & Solution
Answer: Option C
Solution:
$$\eqalign{ & {\text{p}}:{\text{q}}:{\text{r}} \cr & 1:2:4 \cr & x:2x:4x \cr & \therefore \sqrt {5{p^2} + {q^2} + {r^2}} \cr & = \sqrt {5{x^2} + 4{x^2} + 16{x^2}} \cr & = \sqrt {25{x^2}} \cr & = 5x \cr & = 5p \cr} $$
3
The mean proportion between $$\left( {3 + \sqrt 2 } \right)$$   and $$\left( {12 - \sqrt {32} } \right)$$   is = ?
Discuss
Answer & Solution
Answer: Option B
Solution:
$$\eqalign{ & \left( {3 + \sqrt 2 } \right):x:\left( {12 - \sqrt {32} } \right) \cr & a:b:c \cr & {\text{mean proportion}} \cr & \Rightarrow {b^2} = a \times c \cr & \Rightarrow {x^2} = \left( {3 + \sqrt 2 } \right) \times \left( {12 - \sqrt {32} } \right) \cr & \Rightarrow {x^2} = \left( {3 + \sqrt 2 } \right) \times \left( {12 - 4\sqrt 2 } \right) \cr & \Rightarrow {x^2} = \left( {3 + \sqrt 2 } \right) \times 4\left( {3 - \sqrt 2 } \right) \cr & \Rightarrow {x^2} = 4 \times \left\{ {{{\left( 3 \right)}^2} - {{\left( {\sqrt 2 } \right)}^2}} \right\} \cr & \Rightarrow {x^2} = 28 \cr & \Rightarrow x = 2\sqrt 7 \cr} $$
4
a : b : c = 2 : 3 : 4 and 2a - 3b + 4c = 33, then the value of c is = ?
Discuss
Answer & Solution
Answer: Option C
Solution:
$$\eqalign{ & a:b:c \cr & 2:3:4 \cr & {\text{Let }}2x:3x:4x \cr & \Rightarrow 2a - 3b + 4c = 33 \cr & \Rightarrow 2 \times 2x - 3 \times 3x + 4 \times 4x = 33 \cr & \Rightarrow 4x - 9x + 16x = 33 \cr & \Rightarrow 11x = 33 \cr & \Rightarrow x = 3 \cr & \therefore {\text{c}} \Rightarrow 4 \times 3 = 12 \cr} $$
5
In a ratio which is equal to 7 : 8, if the antecedent is 35, what is the consequent?
Discuss
Answer & Solution
Answer: Option B
Solution:
Let the consequent be x
$$\eqalign{ & {\text{Then,}} \cr & \frac{7}{8} = \frac{{35}}{x} \Rightarrow 35 \times 8 \cr & \Rightarrow x = \frac{{35 \times 8}}{7} = 40 \cr} $$
6
If 8a = 9b then the ratio of $$\frac{{\text{a}}}{9}$$ to $$\frac{{\text{b}}}{8}$$ is
Discuss
Answer & Solution
Answer: Option A
Solution:
$$\eqalign{ & = {\text{8a}} = {\text{9b}} \Rightarrow a = \frac{9}{8}b \cr & \therefore \frac{{\text{a}}}{{\text{9}}}:\frac{{\text{b}}}{{\text{8}}} = \frac{{\left( {\frac{9}{8}b} \right)}}{9}:\frac{{\text{b}}}{{\text{8}}} \cr & = \frac{{\text{b}}}{{\text{8}}}:\frac{{\text{b}}}{{\text{8}}} = 1:1 \cr} $$
7
If x : y = 3 : 4, then (2x + 3y) : (3y - 2x) would be equal to.`
Discuss
Answer & Solution
Answer: Option B
Solution:
$$\eqalign{ & = \frac{x}{y} = \frac{3}{4} \cr & = \frac{{2x + 3y}}{{3y - 2x}} \cr & = \frac{{2\left( {\frac{x}{y}} \right) + 3}}{{3 - 2\left( {\frac{x}{y}} \right)}} \cr & = \frac{{2 \times \frac{3}{4} + 3}}{{3 - 2 \times \frac{3}{4}}} \cr & = \frac{9}{2} \times \frac{2}{3} = 3 \cr & = \left( {2x + 3y} \right):\left( {3y - 2x} \right) \cr & = 3:1 \cr} $$
8
Rs. 33630 are divided among A, B and C in such a manner that the ratio of the amount of A to that of B is 3 : 7 and the ratio of the amount of B to that of C is 6 : 5. The amount of money received by B is = ?
Discuss
Answer & Solution
Answer: Option A
Solution:
Given, A : B = 3 : 7
B : C = 6 : 5
A : B = 3 : 7 (multiply with 6) and
B : C = 6 : 5 (multiply with 7)
i.e. A : B = 18 : 42 and
      B : C = 42 : 35
∴ A : B : C = 18 : 42 : 35
⇒18x + 42x + 35x = 33630
⇒ x = 354
∴ Money received by B = 42 × 354 = Rs. 14868
9
200 litres of a mixture contains milk and water in the ratio 17 : 3. After the addition of some more milk to it, the ratio of milk to water in the resulting mixture becomes 7 : 1. The quantity of milk added to it was =?
Discuss
Answer & Solution
Answer: Option B
Solution:
Milk : water = 17 : 3 = 17x : 3x
∴ 17x + 3x = 200
⇒ x =10 litre
Milk = 170 litre and water = 30 litre in initial mixture.
Let 'y' litre of milk added in mixture
i.e. 170 + y : 30 = 7 : 1
⇒ $$\frac{{170 + y}}{{30}} = \frac{7}{1}$$
∴ y = 210 - 170 = 40 litre
10
In an innings of a cricket match,three players A, B and C scored a total of 361 runs. If the ratio of the number of runs scored by A to that scored by B and also number of runs scored by B to that scored by C be 3 : 2, the number of runs scored by A was = ?
Discuss
Answer & Solution
Answer: Option A
Solution:
Given total runs of A, B, C
(A + B + C = 361)
$$\eqalign{ & \Rightarrow {\text{A}}:{\text{B}}:{\text{C}} \cr & \,\,\,\,\,\,\,\,\,3:2 \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,3:2 \cr & \underline {\overline {\,\,\,\,\,\,\,\,\,\,9:6:4{\text{ }}} } \cr & \therefore 9x + 6x + 4x = 361 \cr & \Rightarrow 19x = 361 \cr & \Rightarrow x = 19 \cr & \therefore {\text{Runs scored by A }} \cr & = 9x \cr & = 9 \times 19 \cr & = 171 \cr} $$