A and B can complete a piece of work in 12 and 18 days

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A and B can complete a piece of work in 12 and 18 days respectively. A begins to do the work and they work alternatively one at a time for one day each. The whole work will be completed in

A

B

C

D

Nithin K ? Nov 23 '2016 at 21:4

Answer is: $14 \frac{1}{3} days$

Explanation:

A can complete total work in 12 days

One day work of A = $\frac{1}{2}$part

B can complete work in 18 days

One day work of B = $\frac{1}{18}$part

A and B together can complete work in one day,

=$\frac{1}{12} + \frac{1}{18}$

=$\frac{18+12}{216}$=$\frac{30}{216}$=$\frac{15}{108}$

=$\frac{5}{36}$part

Evidently, the work done by A and B during 7 pairs (14 days)

=$7 \times \frac{5}{36} = \frac{35}{36}$

Remaining work = $\big(1-\frac{35}{36}\big) = \frac{1}{36}$

Now, on 15th  day it is  A's turn.

Now $\frac{1}{12}$work is done by A in 1 day.

$\frac{1}{36}$ work will be done by A in $\big[12 \times \frac{1}{36}\big] = \frac{1}{3}$ day

So, total time taken = $14 \frac{1}{3}$ days

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The expenses on rice, fish and oil of a family are in the

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The expenses on rice, fish and oil of a family are in the ratio 12 : 17 : 3. The prices of these articles are increased by 20%, 30% and 50% respectively. The total expenses of family on these articles are increased by

A

B

C

D

Nithin K ? Nov 22 '2016 at 22:16

Answer is : $28 \frac{1}{8}\%$

Explanation:

Ratio of the expenses on rice, fish, and oil = 12 : 17 : 3
Let the expences be 12x, 17x and 3x

Total expenditure = 12x + 17x + 3x = 32x

Increased expenditure on rice = 12x × (1 + 20/100) = 14.4x
Increased expenditure on fish = 17x × (1 + 30/100) = 22.1x
Increased expenditure on oil =  3x × (1 + 50/100) = 4.5x

Total expenditure after increase = (14.4x + 22.1x + 4.5x) = 41x

Increased expenditure = 41x - 32x = 9x

Percentage increase in the expenditure = $\frac{9x * 100}{32} = 28.125\%$

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The value of ★ in the sequence

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A0

B1

C-1

D-3

Nithin K ? Nov 21 '2016 at 20:17

Answer is : 1

Explanation:

Sequence Given is,
$27, 9, 3, _, \frac{1}{3}, \frac{1}{9}, \frac{1}{27}$
rewrite sequence using 3's power
$3^3, 3^2, 3^1, \text{_ },3^{-1}, 3^{-2}, 3^{-3}$
the missed number is $3^0 = 1$

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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)
$\frac{j}{s}= \frac{0.5 j}{6} + \frac{0.5j}{3}$
$\frac{j}{s}=\frac{0.5j}{6} + \frac{j}{6}$
$\frac{j}{s} = \frac{1.5j}{6}$
$\frac{1}{s} = \frac{1.5}{6}$
$6 = 1.5 s$
$s = \frac{6}{1.5}$
$s = \frac{60}{15}$
$s = 4$
---------------------------------------------------------------------------------------

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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