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

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB ASM Exam (Ajmer) 2007 click here to view all questions

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

View Answer

Discuss

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

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB ASM Exam (Ajmer) 2007 click here to view all questions

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 = \(\frac{9x * 100}{32} = 28.125\%\)

View Answer

Discuss

The value of ★ in the sequence

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB ASM Exam (Ajmer) 2007 click here to view all questions

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 \(3^0 = 1\)

View Answer

Discuss

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

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB ASM Exam (Ajmer) 2007 click here to view all questions

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.

View Answer

Discuss

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

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB ASM Exam (Ajmer) 2007 click here to view all questions

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.

View Answer

Discuss

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

Report

Report an issue

Name

Email

Message

Submit

Cancel

RRB ASM Exam (Ajmer) 2007 click here to view all questions

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 
\(\frac{ 273 + x }{7} = 47 \)
\(273 + x = 329  \)

\(x = 56\)

View Answer

Discuss