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Q:

Three taps A,B and C can fill a tank in 12,15 and 20 hours respectively. If A is open all the time and B ,C are open for one hour each alternatively, the tank will be full in:

A) 6 hrs	B) 20/3 hrs
C) 7 hrs	D) 15/2 hrs

Answer & Explanation Answer: C) 7 hrs

Explanation:

$(A + B)' s 1 h o u r w o r k = (\frac{1}{12} + \frac{1}{15}) = \frac{9}{60} = \frac{3}{20}$

$(A + C)' s 1 h o u r w o r k = (\frac{1}{12} + \frac{1}{20}) = \frac{8}{60} = \frac{2}{15}$

$p a r t f i l l e d i n 2 h r s = (\frac{3}{20} + \frac{2}{15}) = \frac{17}{60}$

$p a r t f i l l e d i n 6 h r s = (3 * \frac{17}{60}) = \frac{17}{20}$

$r e m a i n i n g p a r t = (1 - \frac{17}{20}) = \frac{3}{20}$

Now, it is the turn of A and B (3/20) part is filled by A and B in 1 hour.

Therefore, Total time taken to fill the tank =(6+1)hrs= 7 hrs

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Filed Under: Pipes and Cistern

Q:

12 buckets of water fill a tank when the capacity of each tank is 13.5 liters. How many buckets will be needed to fill the same tank,if the capacity of each bucket is 9 liters?

A) 8	B) 15
C) 16	D) 18

Answer & Explanation Answer: D) 18

Explanation:

Capacity of the tank =(12 x 13.5) liters =162 liters.

Capacity of each bucket =9 liters

Number of buckets needed = 162/9 =18.

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Filed Under: Pipes and Cistern

Q:

A water tank is two-fifth full.Pipe A can fill a tank in 10 minutes and pipe B can empty it in 6 minutes.If both the pipes are open,how long will it take to empty or fill the tank completely?

A) 6 min.to empty	B) 6 min.to fill
C) 9 min.to empty	D) 9 min.to fill

Answer & Explanation Answer: A) 6 min.to empty

Explanation:

Clearly,pipe B is faster than pipe A and so,the tank will be emptied.

part to be emptied = 2/5

part emptied by (A+B) in 1 minute= $(\frac{1}{6} - \frac{1}{10}) = \frac{1}{15}$

$\frac{1}{15} : \frac{2}{5} : : 1 : x$

$\frac{2}{5} * 15 = 6 m i n s$

so, the tank will be emptied in 6 min

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Filed Under: Pipes and Cistern

Q:

If $a = \frac{\sqrt{5} + 1}{\sqrt{5} - 1} b = \frac{\sqrt{5} - 1}{\sqrt{5} + 1} t h e n f i n d t h e v a l u e o f [\frac{a^{2} + a b + b^{2}}{a^{2} - a b + b^{2}}] i s : :$

A) 3/4	B) 4/3
C) 3/5	D) 5/3

Answer & Explanation Answer: B) 4/3

Explanation:

By simplifying, we get 4/3

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Filed Under: Square Roots and Cube Roots
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

Q:

If x = $7 - 4 \sqrt{3} t h e n f i n d t h e v a l u e o f (x + \frac{1}{x}) ?$

A) 3sqrt{3}	B) 8sqrt{3}
C) 14	D) 14+8sqrt{3}

Answer & Explanation Answer: C) 14

Explanation:

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Filed Under: Square Roots and Cube Roots
Exam Prep: Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

Q:

$\frac{3 + \sqrt{6}}{5 \sqrt{3} - 2 \sqrt{12} - \sqrt{30} + \sqrt{50}} = ?$

A) 3	B) 3sqrt{2}
C) 6	D) None of these

Answer & Explanation Answer: D) None of these

Explanation:

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Filed Under: Square Roots and Cube Roots
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

Q:

If $\frac{5 + 2 \sqrt{3}}{7 + 4 \sqrt{3}} = a + b \sqrt{3} t h e n a & b = ?$

A) a=-11,b=-6	B) a=-11,b=6
C) a=11,b=-6	D) a=11,b=6

Answer & Explanation Answer: C) a=11,b=-6

Explanation:

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Filed Under: Square Roots and Cube Roots
Exam Prep: AIEEE , Bank Exams , CAT
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Q:

$[\frac{3 \sqrt{2}}{\sqrt{6} - \sqrt{3}} - \frac{4 \sqrt{3}}{\sqrt{6} - \sqrt{2}} - \frac{6}{\sqrt{8} - \sqrt{12}}] = ?$

A) sqtr{3}-sqrt{2}	B) sqtr{3}+sqrt{2}
C) 5sqrt{3}	D) 1

Answer & Explanation Answer: C) 5sqrt{3}

Explanation:

Given Exp = $\frac{3 \sqrt{2}}{\sqrt{6} - \sqrt{3}} \times \frac{\sqrt{6} + \sqrt{3}}{\sqrt{6} + \sqrt{3}} - \frac{4 \sqrt{3}}{\sqrt{6} - \sqrt{2}} \times \frac{\sqrt{6} + \sqrt{2}}{\sqrt{6} + \sqrt{2}} - \frac{6}{2 (\sqrt{2} - \sqrt{3})}$

= $\frac{3 \sqrt{2} (\sqrt{6} + \sqrt{3})}{6 - 3} - \frac{4 \sqrt{3} (\sqrt{6} + \sqrt{2})}{6 - 2} + \frac{3}{(\sqrt{3} - \sqrt{2})} \times \frac{(\sqrt{3} + \sqrt{2})}{(\sqrt{3} + \sqrt{2})}$

= $\sqrt{2} (\sqrt{6} + \sqrt{3}) - \sqrt{3} (\sqrt{6} + \sqrt{2}) + 3 (\sqrt{3} + \sqrt{2})$

= $\sqrt{12} + \sqrt{6} - \sqrt{18} - \sqrt{6} + 3 \sqrt{3} + 3 \sqrt{2}$

= $5 \sqrt{3}$

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Filed Under: Square Roots and Cube Roots

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