There were 24 students in a class. One of them, who was 18 y

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There were 24 students in a class. One of them, who was 18 yr old, left the class and his place was filled up by a newcomer. If the average of the class thereby,was lowered by one month. The age of the newcomer is-

A14 yr

B15 yr

C16 hr

D17 yr

Nithin K ? Nov 20 '2016 at 21:58

Answer is : 16 hr

Explanation:

There were 24 students in a class.
No. of students in class = 24 ....................(i)

If the average of the class thereby,was lowered by one month
Average age decreased by = 1 month = \(\frac{1}{12} \)years..................(ii)

Let new comer age was x.
One of them, who was 18 yr old, left the class and his place was filled up by a newcomer.

= 18 - x ...............................(iii)

No. of students in class* aged decreased = difference of replacement
From equation (i),(ii) and (iii)
\(24 * \frac{1}{12} = 18 - x\)
\(2 = 18 - x\)
\(x = 16 years.\)
Age of new comer age was 16 years.

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A man covers half of his journey at 6 km/h and the remaining

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A man covers half of his journey at 6 km/h and the remaining half at 3 km/h. His average speed is

A9 km/h

B4.5 km/h

C4 km/h

D3 km/h

Nithin K ? Nov 20 '2016 at 21:47

Answer is : 4 km/h

Explanation:

Given,
A man covers half of his journey at 6 km/h = \(\frac{0.5j}{6} \).......(i)
the remaining half at 3 km/h = \(\frac{0.5j}{3}\) ................(ii)

Average speed = equation (i) + equation (ii)
\(\frac{j}{s}= \frac{0.5 j}{6} + \frac{0.5j}{3}\)
\(\frac{j}{s}=\frac{0.5j}{6} + \frac{j}{6}\)
\(\frac{j}{s} = \frac{1.5j}{6}\)
\(\frac{1}{s} = \frac{1.5}{6}\)
\(6 = 1.5 s\)
\(s = \frac{6}{1.5}\)
\(s = \frac{60}{15}\)
\(s = 4\)
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Shortcut Formula: If Two speed is geven
\(\text{Average speed }= \frac{2xy}{x+y};\)
\(= \frac{2*6*3}{6+3};\)
\(= \frac{36}{9}\)
= 4 kmp/h.

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The average of 6 observations is 45.5. If one new observatio

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The average of 6 observations is 45.5. If one new observation is added to the previous observations, then the new average becomes 47. The new observation is

A58

B56

C50

D46

Nithin K ? Nov 20 '2016 at 21:42

Answer is : 56

Explanation :

Given, The average of 6 observations is 45.5. 
Sum of Total Observation = \(6 \times 45.5 = 273\)

If one new observation is added to the previous observations, then the new average becomes 47.
Let the new observation be x 
\(\frac{ 273 + x }{7} = 47 \)
\(273 + x = 329  \)

\(x = 56\)

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The average of 100 numbers is 44. The average of these 100 n

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The average of 100 numbers is 44. The average of these 100 numbers and 4 other new number is 50. The average of the four new numbers will be-

A800

B200

C176

D24

Nithin K ? Nov 20 '2016 at 21:32

Answer is : 200

Explanation:

Sum of four new numbers  \(=50 \times 104 – 100 \times 44 \)

\(= 5200 – 4400 \)

\(= 800 \)

\(\therefore\text{ Average}= \frac{800}{4} =200\)

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Rs.395 are divided among A, B and C in such a manner that B

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Rs.395 are divided among A, B and C in such a manner that B gets 25 percent more than A and 20 percent more than C. The share of A will be-

ARs.195

BRs.180

CRs.98

DRs.120

Nithin K ? Nov 20 '2016 at 21:7

Answer is : Rs.120

\(\text{Let A gets Rs x} \)

\(\therefore \text{B gets} = \frac{125x}{100} = \text{Rs }\frac{5x}{4}\)

\(\text{C gets }= \frac{100}{120} \times \frac{5x}{4} = \frac{25}{24}x\)

\(\therefore x + \text{ }\frac{5}{4}x+\text{ }\frac{25}{24}x =395 \)

\(=>\frac{24x+30x+25x}{24} =395\)

\(=>\frac{79}{24}x=395\)

\(x = \frac{395 \times 24}{79}\)

\(x = 120\)

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In an innings of a cricket match, three players A, B and C s

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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 be 3 : 2. The number of runs scoredby A was-

A171

B181

C185

D161

Nithin K ? Nov 20 '2016 at 20:48

Answer is : 171
Explanation:

Given,
(A:B):(B:C) = 3:2
A : B = (3 : 2) 
B : C = (3 : 2)

On Multiplying (A:B) with 3 and (B:C with 2)
A : B = 9 : 6
B : C = 6 : 4
Now,
A : B :C = 9 : 6 : 4
Total run = 361
9x + 6X + 4X = 361
19x = 361
x = 19
Number of Runs Scored by A = 9x =9*19 = 171 runs.

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The price of certain item is increased by 15%. If a consumer

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The price of certain item is increased by 15%. If a consumer wants to keep his expenditure on the item the same as before, how much percent must he reduce his consumption of that item?

A

B

C

D

Nithin K ? Nov 20 '2016 at 20:44

Answer is : 13 (1/23)

Explanation:
Formula
Percentage decrease = \(\frac{p\times m}{p+m},\) where m is the original percentage and p is price.

Let us Consider Initial price is 100
and m is 15% => 15
Therefore
Percentage decrease in sugar case
\(=\frac{100 \times 15}{100+15}\)
\(=\frac{1500}{115}\)
\(=\frac{300}{23}\)
=13 + \(\frac{1}{23} \)% decrease.

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