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Q:

The ages of X and Y are in the proportion of 6:5 and total of their ages is 44 years. The proportion of their ages after 8 years will be

A) 3:6 B) 6:3
C) 8:7 D) 9:5
 
Answer & Explanation Answer: C) 8:7

Explanation:

Let current ages of X and Y correspondingly, is 6A & 5A
Given: 6A + 5A = 44
=> A = 4
Proportion of ages after 0.8 decades will be
6A + 8 : 5A + 8   32:28 (or) 8:7

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Filed Under: Problems on Ages

Q:

Sivagami is 2 years elder than Meena. After 6 years the total of their ages will be 7 times of their current age. Then age of Sivagami is :

A) 19 years B) 17 years
C) 15 years D) data inadequate
 
Answer & Explanation Answer: D) data inadequate

Explanation:

Let Meena’s age = A.
Then Sivagami’s age = A + 2
After 6 years the total of their ages will be 7 times of what?
Not clear.
So the given data are inadequate.

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Filed Under: Problems on Ages

Q:

If 47. 2506 = 4*A + 7/B + 2*C + 5/D + 6*E, then the value of 5*A + 3*B + 6*C + D + 3*E is :

A) 55.6003 B) 53.603
C) 153.6003 D) 213.003
 
Answer & Explanation Answer: C) 153.6003

Explanation:

4*A + 7/B + 2*C + 5/D + 6*E =47.2506
=> 4 * A + 7/B + 2 *C + 5/D + 6*E = 40 + 7 + 0.2 + 0.05 + 0.0006
Comparing the terms on both sides, we get :
4*A =40, 7/B = 7, 2*C = 0.2, 5/D = 0.05, 6*E = 0.0006
A = 10,
B = 1,
C = 0.1,
D = 100,
E = 0.0001.
5*A + 3*B + 6*C + D + 3*E =(5*10) + (3*1) + (6*0.1) +100 +(3*0.0001)
=50 + 3 + 0.6 + 100 + 0.003 = 153.6003.

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Filed Under: Decimal Fractions

Q:

The difference between a positive proper fraction and its reciprocal is 9 / 20. Then the fraction is :

A) 3/5 B) 3/10
C) 4/5 D) 5/4
 
Answer & Explanation Answer: C) 4/5

Explanation:

Let the required fraction be x. Then, (1 / x )- x = 9/20
1 - x^(2) / x = 9 / 20  =>  20 - 20 * x^(2) = 9 * x.
20 * x^(2) + 9 *x - 20 = 0.
=> (4 * x + 5) (5 * x - 4) = 0.
=> x = 4 / 5.

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Filed Under: Numbers

Q:

If n is natural number , then 6n2+6n is always divisible by :

A) 6 only B) 6 and 12 both
C) 12 only D) by 18 only
 
Answer & Explanation Answer: B) 6 and 12 both

Explanation:

6n2+6n=6nn+1, which is always divisible by 6 and 12 both, since n(n+1) is always even.

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Filed Under: Numbers

Q:

A boy multiplied 987 by a certain number and obtained 559981 as his answer. If in the answer both 98 are wrong and the other digits are correct , then the correct answer would be :

A) 553681 B) 555181
C) 555681 D) 556581
 
Answer & Explanation Answer: C) 555681

Explanation:

987 = 3 * 7 * 47.
So, the required number must be divisible by each one of 3, 7, 47
553681 => (Sum of digits = 28, not divisible by 3)
555181 => (Sum of digits = 25, not divisible by 3)
555681 is divisible by each one of 3, 7, 47.

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Filed Under: Numbers

Q:

476 ** 0 is divisible by both 3 and 11.The non zero digits in the hundred's and ten's places are respectively:

A) 6 and 2 B) 8 and 2
C) 6 and 5 D) 8 and 5
 
Answer & Explanation Answer: D) 8 and 5

Explanation:

Let the number  be 476ab0 

 

476ab0 is divisible by 3 

=> 4 + 7 + 6 + a + b + 0 is divisible by 3

=> 17 + a + b is divisible by 3 ------------------------(i)

 

476ab0 is divisible by 11

[(4 + 6 + b) -(7 + a + 0)] is 0 or divisible by 11

=> [3 + (b - a)] is 0 or divisible by 11  --------------(ii)

 

Substitute the values of a and b with the values given in the choices and select the values which satisfies both Equation 1 and Equation 2.

 

if a=6 and b=2, 

17 + a + b = 17 + 6 + 2 = 25 which is not divisible by 3 --- Does not meet equation(i).Hence this is not the answer

 

if a=8 and b=2, 

17 + a + b = 17 + 8 + 2 = 27 which is divisible by 3 --- Meet equation(i)

[3 + (b - a)] = [3 + (2 - 8)] = -3 which is neither 0 nor divisible by 11---Does not meet equation(ii).Hence this is not the answer

 

if a=6 and b=5, 

17 + a + b = 17 + 6 + 5 = 28 which is not divisible by 3 --- Does not meet equation (i) .Hence this is not the answer

 

 

if a=8 and b=5, 

17 + a + b = 17 + 8 + 5 = 30 which is divisible by 3 --- Meet equation 1

[3 + (b - a)] = [3 + (5 - 8)] = 0 ---Meet equation 2

Since these values satisfies both equation 1 and equation 2, this is the answer

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Filed Under: Numbers

Q:

If the product 4864*9 P 2 is divisible by 12, the value of p:

A) 1 B) 2
C) 3 D) 4
 
Answer & Explanation Answer: A) 1

Explanation:

Clearly 4864 is divisible by 4
So, 9 P 2 must be divisible by 3. So (9+P+2) must be divisible by 3.
So P=1.

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Filed Under: Numbers