is equal to

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is equal to

A

B

C

D

No answer description available for this question. Let us discuss.

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Out of seven given numbers, the average of the first four nu

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Out of seven given numbers, the average of the first four numbers is 4 and that of the last four numbers is also 4. If the average of all the seven numbers is 3, fourth number is

A3

B4

C7

D11

Nithin K ? Nov 20 '2016 at 19:20

Answer is : 11

Explanation :

Since the average of first four numbers is 4, 
the sum of first four numbers is 4*4 = 16
a1 + a2 + a3 + a4 =16 ..................(i)

Since the average of the last four numbers is 4, 
the sum of the last four numbers is 4*4 = 16
a4 + a5 + a6 + a7 = 16...................(ii)

Add (i) and (ii) and re-group. You will get
(a1 + a2 + a3 + a4 + a5 + a6 + a7) + a4 = 32 .......(iii)

Since the average of the seven numbers is 3, their sum is 3*7 = 21
Apply This Sum in eqation (iii)

we get,
21 + a4 = 32
a4 = 32 - 21
a4 = 11

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The length of a rectangle is increased by 10% and breadth

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The length of a rectangle is increased by 10% and breadth decreased by 10%. Then the area of the new rectangle is

Aneither decreased nor increased

Bincreased by 1%

Cdecreased by 1%

Ddecreased by 10%

Nithin K ? Nov 20 '2016 at 19:16

Answer is : decreased by 1%

Explanation :

Suppose
Length is 10cm.
Breadth is 20cm.
Then old Area = Length x Breadth = \(10 \times 20\) = 200 ......................(i)

If Length increased by 10% = 11cm
if Breadth decreased by 10% = 18cm
So, new Area = \(11 \times 18 \)= 198 ..............................(ii)

From (i) and (ii)
old area = 200
new area = 198
So new area is decreased by 1%

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The ratio of the number of boys and girls in a school is 3

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The ratio of the number of boys and girls in a school is 3 : 2. If 20% of the boys and 30% of the girls are scholarship holders, then the percentage of students, who do not get scholarship, is

A50

B72

C75

D76

Nithin K ? Nov 20 '2016 at 19:15

Answer is : 76

Explanation :

Let the number of boys & girls be 3x and 2x.

Number of those who are not scholarship holders

\(=(\text{80% of 3x} + \text{70% of 2x})\)

\( = \frac{12x}{5} + \frac{7x}{5}\)

\( = \frac{19x}{5}\)

Required Percentage \(= \frac{19x}{5} * \frac{1}{5x} * 100\% = 76%\)

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The speeds of A and B are in the ratio 3 : 4. A takes 20 min

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The speeds of A and B are in the ratio 3 : 4. A takes 20 min more than B to reach a destination. In what time does A reach the destination?

A

B2 h

C

D

Nithin K ? Nov 20 '2016 at 19:6

Answer is : \(1\frac{1}{3} h\)

Ratio of speed = 3:4;
Ratio of time taken = 4:3 (distance remains constant.)
Let time taken by A and B be 4x and 3x hour respectively.

Then,
\(4x-3x = \frac{20}{60};\)
\(=> x = \frac{1}{3};\)
Hence, time taken by A = 4x
\(= 4*\frac{1}{3} = 1\frac{1}{3} hours.\)

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1 litre of water is added to 5 litre of alcohol - water solu

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1 litre of water is added to 5 litre of alcohol - water solution containing 40% alcohol strength. The strength of alcohol in the new solution will be

A30%

B33%

C

D

Nithin K ? Nov 20 '2016 at 19:2

Answer is : \(33 \frac{1}{3}\%\)

Alcohol in the earlier mixture = 40% of 5 liters = 2 liters
Mixture after addition of 1 liter of water = 5 + 1 = 6 liters
Therefore strength of alcohol in the new mixture in percentage = \(\frac{2}{6}*100\)
\(=\frac{100}{3} %\)
\(=33\frac{1}{3}\%\)

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If a : b : c = 2 : 3 : 4 and 2a - 3b + 4c = 33, then the value of c is-

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If a : b : c = 2 : 3 : 4 and 2a - 3b + 4c = 33, then the value of c is-

A6

B9

C12

D66/7

Nithin K ? Nov 20 '2016 at 18:52

Answer is : 12

Explanation:

\(a:b:c = 2:3:4\)

\(\therefore \frac{a}{2} = \frac{b}{3} = \frac{c}{4} =k\)

\(=>a=2k, b=3k, c=4k\)

\(\text{Given, } 2a-3b+4c =33\)

\(=> 2 * 2k - 3*3k+4*4k =33\)

\(=> 4k =9k+16k=33\)

\(=>11k =33\)

\(=> k = \frac{33}{11} =3\)

\(\therefore c = 4k \)

\(=> 4*3 =>12\)

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