L Search

Q:

Relation Between Efficiency and Time

A is twice as good a workman as B and is therefore able to finish a piece of work in 30 days less than B.In how many days they can complee the whole work; working together?

Answer

Ratio of times taken by A and B = 1 : 2.

The time difference is (2 - 1) 1 day while B take 2 days and A takes 1 day.

If difference of time is 1 day, B takes 2 days.

If difference of time is 30 days, B takes 2 x 30 = 60 days.

So, A takes 30 days to do the work.

A's 1 day's work = 1/30

B's 1 day's work = 1/60

(A + B)'s 1 day's work = 1/30 + 1/60 = 1/20

A and B together can do the work in 20 days.

Workspace

Report Error

View answer Workspace Report Error Discuss

Subject: Time and Work

Q:

Concept of Efficiency

A can do a job in 12 days and B can do the same job in 6 days, in how many days working together they can complete the job?

Answer

A's 1 days work = 1/12

B's 1 days work =1/6

Therefore, (A+B)'s 1 day's work= 1/12 + 1/6 = 1/4

Therefore, Time taken by both to finish the whole work = $\frac{1}{\frac{1}{4}}$ = 4 days

Alternatively :

Efficiency of A =100/12 =8.33%

Efficiency of B =100/6=16.66%

Combined efficiency of A and B both = 8.33+16.66=25%

Therefore, Time taken by both to finish the work (working together) =100/25= 4days

Workspace

Report Error

View answer Workspace Report Error Discuss

Subject: Time and Work

Q:

From a container, 6 liters milk was drawn out and was replaced by water. Again 6 liters of mixture was drawn out and was replaced by the water. Thus the quantity of milk and water in the container after these two operations is 9:16. The quantity of mixture is:

A) 15	B) 16
C) 25	D) 31

Answer & Explanation Answer: A) 15

Explanation:

Let quantity of mixture be x liters.

Suppose a container contains x units of liquid from which y units are taken out and replaced by Water. After operations , the quantity of pure liquid = $x {(1 - \frac{y}{x})}^{n}$ units, Where n = no of operations .

So, Quantity of Milk = $x {(1 - \frac{6}{x})}^{2}$

Given that, Milk : Water = 9 : 16

=> Milk : (Milk + Water) = 9 : (9+16)

=> Milk : Mixture = 9 : 25

Therefore, $\frac{x {(1 - \frac{6}{x})}^{2}}{x} = \frac{9}{25}$

=> x = 15 liters

Report Error

View Answer Report Error Discuss

Filed Under: Alligation or Mixture

Q:

The ratio of petrol and kerosene in the container is 3:2 when 10 liters of the mixture is taken out and is replaced by the kerosene, the ratio become 2:3. Then total quantity of the mixture in the container is:

A) 25	B) 30
C) 45	D) cannot be determined

Answer & Explanation Answer: B) 30

Explanation:

pool : kerosene

3 : 2(initially)

2 : 3(after replacement)

$\frac{R e m a i n i n g Q u a n t i t y}{I n i t i a l Q u a n t i t y} = (1 - \frac{R e p l a c e d Q u a n t i t y}{T o t a l Q u a n t i t y})$

(for petrol) $\frac{2}{3} = (1 - \frac{10}{k})$

=> K = 30

Therefore the total quantity of the mixture in the container is 30 liters.

Report Error

View Answer Report Error Discuss

Filed Under: Alligation or Mixture

Q:

In a mixture of milk and water, there is only 26% water. After replacing the mixture with 7 liters of pure milk , the percentage of milk in the mixture become 76%. The quantity of mixture is:

A) 65 liters	B) 91 liters
C) 38 liters	D) None of these

Answer & Explanation Answer: B) 91 liters

Explanation:

Milk Water

74% 26% (initially)

76% 24% ( after replacement)

Left amount = Initial amount $(1 - \frac{r e p l a c e d a m o u n t}{t o t a l a m o u n t})$

24 = 26 $(1 - \frac{7}{k})$

=> k = 91

Report Error

View Answer Report Error Discuss

Filed Under: Alligation or Mixture

Q:

The diluted wine contains only 8 liters of wine and the rest is water. A new mixture whose concentration is 30%, is to be formed by replacing wine. How many liters of mixture shall be replaced with pure wine if there was initially 32 liters of water in the mixture ?

A) 4	B) 5
C) 8	D) None of these

Answer & Explanation Answer: B) 5

Explanation:

Wine Water

8L 32L

1 : 4

20 % 80% (original ratio)

30 % 70% (required ratio)

In ths case, the percentage of water being reduced when the mixture is being replaced with wine.

so the ratio of left quantity to the initial quantity is 7:8

Therefore , $\frac{7}{8} = [1 - \frac{K}{40}]$

=> K = 5 Lit

Report Error

View Answer Report Error Discuss

Filed Under: Alligation or Mixture
Exam Prep: CAT , Bank Exams
Job Role: Bank PO , Bank Clerk

Q:

A jar was full with honey. A person used to draw out 20% of the honey from the jar and replaced it with sugar solution. He has repeated the same process 4 times and thus there was only 512 gm of honey left in the jar, the rest part of the jar was filled with the sugar solution. The initial amount of honey in the jar was filled with the sugar solution. The initial amount of honey in the jar was:

A) 1.25 kg	B) 1 kg
C) 1.5 kg	D) None of these

Answer & Explanation Answer: A) 1.25 kg

Explanation:

Let the initial amount of honey in the jar was K, then

$512 = K {(1 - \frac{1}{5})}^{4}$ $[∵ 20 % = \frac{20}{100} = \frac{1}{5}]$

or

$512 = K {(\frac{4}{5})}^{4}$

Therefore, K = 1250

Hence initially the honey in the jar= 1.25 kg

Report Error

View Answer Report Error Discuss

Filed Under: Alligation or Mixture

Q:

From a container of wine, a thief has stolen 15 liters of wine and replaced it with same quantity of water.He again repeated the same process. Thus in three attempts the ratio of wine and water became 343:169. The initial amount of wine in the container was:

A) 75 liters	B) 100 liters
C) 150 liters	D) 120 liters

Answer & Explanation Answer: D) 120 liters

Explanation:

$\frac{W i n e (l e f t)}{W a t e r (a d d e d)} = \frac{343}{169}$

It means $\frac{W i n e (l e f t)}{W i n e (i n i t i a l a m o u n t)} = \frac{343}{512}$ $[∵ 343 + 169 = 512]$

Thus ,

$343 x = 512 x {(1 - \frac{15}{K})}^{3}$

$\Rightarrow \frac{343}{512} = {(\frac{7}{8})}^{3} = {(1 - \frac{15}{k})}^{3}$

=> K = 120

Thus the initial amount of wine was 120 liters.

Report Error

View Answer Report Error Discuss

Filed Under: Alligation or Mixture

Searching for "L"

Quick Links