11
Q:

For any two numbers m , n ; (m+n) : (m-n) : mn = 7: 1: 60 . Find the value of 1/m : 1/n

A) 4:3 B) 8:7
C) 3:4 D) 7:8

Answer:   C) 3:4



Explanation:

\inline \fn_jvn \frac{m+n}{m-n}=\frac{7x}{x} \: \: \Rightarrow \: \: \frac{m}{n}=\frac{4x}{3x}

Again      \inline \fn_jvn mn=4x\times 3x=12x^{2}

and         mn =60x

so           \inline \fn_jvn 60x=12x^{2}   \inline \fn_jvn \Rightarrow  x= 5.

\inline \fn_jvn \therefore           m= 20  and    n= 15

Hence,    \inline \fn_jvn \frac{1}{m}:\frac{1}{n}=\frac{1}{20}:\frac{1}{15}=3:4

Q:

The sum of three numbers is 98. If the ratio of the first to the second is 2:3. And that of the second to the third is 5:8, then the second number is:

A) 10 B) 15
C) 20 D) 30
 
Answer & Explanation Answer: D) 30

Explanation:

Let the three parts M, N, O.
Then, M:N = 2:3 and N:O = 5:8
= (5 x 3/5) : (8 x 3/5) = 3:24/5

M:N:O = 2:3:24/5

= 10:15:24 => N = 98 x 15/49 = 30.

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2 48
Q:

Rs. 2600 is divided into three parts A, B and C. How much A is more than C if their ratio is 1/2:1/3:1/4 ?

A) 600 B) 300
C) 150 D) 75
 
Answer & Explanation Answer: A) 600

Explanation:

1/2:1/3:1/4 = 6:4:3

As the difference is 3

=> 3/13x2600 = 600

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2 103
Q:

If 6 men and 3 boys working together, can do four times as much work per hour as a man and a boy together. Find the ratio of the work done by a man and that of a boy for a given time  ?

A) 1 : 2 B) 2 : 1
C) 3 : 1 D) 1 : 3
 
Answer & Explanation Answer: A) 1 : 2

Explanation:

6M + 3B = 4(1M + 1B)
6M + 3B = 4M + 4B
2M = 1B

M/B = 1/2

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5 156
Q:

If k : l = 4 : 3 and l : m = 5 : 3, then find k : l : m ?

A) 18 : 24 : 11 B) 9 : 15 : 1
C) 20 : 15 : 9 D) 21 : 7 : 3
 
Answer & Explanation Answer: C) 20 : 15 : 9

Explanation:

Given k : l = 4 : 3
l : m = 5 : 3

Then k : l : m = 20 : 15 : 9

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4 226
Q:

A sum is divided among K, L and M in such a way that for each rupee K gets, L gets 45 paisa and M gets 30 paisa. If the share of L is Rs. 27,  what is the total amount  ?

A) Rs. 159 B) Rs. 96
C) Rs. 147 D) Rs. 105
 
Answer & Explanation Answer: D) Rs. 105

Explanation:

K : L : M = 100 : 45 : 30
              = 20 : 9 : 6

Given L share is 27

=> 9  ------  27
      35 ------  ?

      => 105

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3 257