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Q:

(x-2) men can do a piece of work in x days and (x+7) men can do 75% of the same work in (x-10)days. Then in how many days can (x+10) men finish the work?

A) 27 days B) 12 days
C) 25 days D) 18 days

Answer:   B) 12 days



Explanation:

\inline \fn_jvn \frac{3}{4}\times (x-2)x=(x+7)(x-10)

\inline \fn_jvn \Rightarrow    \inline \fn_jvn x^{2}-6x-280=0 

\inline \fn_jvn \Rightarrow    x= 20   and   x=-14

so, the acceptable values is x=20

\inline \fn_jvn \therefore Total work = \inline \fn_jvn (x-2)\times x = 18 x 20 =360 unit

Now   360 = 30 x k          \inline \fn_jvn \because (30=20+10)

\inline \fn_jvn \Rightarrow  k=12 days

Q:

X can complete the work in 10 days, Y can do the same in 15 days. If they are hired for 5 days to do the work together, what is the work that left unfinished?

A) 1/3 B) 2/3
C) 1/6 D) 5/6
 
Answer & Explanation Answer: C) 1/6

Explanation:

Given X can do in 10 days

=> 1 day work of X = 1/10

Y can do in 15 days

=> 1 day work of Y = 1/15

1day work of (X + Y) = 1/10 + 1/15 = 1/6

Given they are hired for 5 days

=> 5 days work of (X + Y) = 5 x 1/6 = 5/6

Therefore, Unfinished work = 1 - 5/6 = 1/6 

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6 185
Q:

If 10 men take 15 days to complete a work. In how many days will 37 men complete the work?

A) 3 days B) 4 days
C) 5 days D) 6 days
 
Answer & Explanation Answer: B) 4 days

Explanation:

Given 10 men take 15 days to complete a work

=> Total mandays = 15 x 10 = 150

Let the work be 150 mandays.

=> Now 37 men can do 150 mandays in 150/37 =~ 4 days

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11 136
Q:

Three taps P, Q and R can fill a tank in 12 hrs, 15 hrs and 20 hrs respectively. If P is open all the time and Q and R are open for one hour each alternately, starting with Q, then the tank will be full in how many hours ?

A) 9 hrs B) 7 hrs
C) 13 hrs D) 11 hrs
 
Answer & Explanation Answer: B) 7 hrs

Explanation:

Given,

P can fill in 12 hrs

Q can fill in 15 hrs

R can fill in 20 hrs

=> Volume of tank = LCM of 12, 15, 20 = 60 lit

=> P alone can fill the tank in 60/12 = 5 hrs

=> Q alone can fill the tank in 60/15 = 4 hrs

=> R alone can fill the tank in 60/20 = 3 hrs

Tank can be filled in the way that

(P+Q) + (P+R) + (P+Q) + (P+R) + ....

=> Tank filled in 2 hrs = (5+4) + (5+3) = 9 + 8 = 17 lit

=> In 6 hrs = 17 x 6/2 = 51 lit

=> In 7th hr = 51 + (5+4) = 51 + 9 = 60 lit

=> So, total tank will be filled in 7 hrs.

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7 334
Q:

P and Q can complete a job in 24 days working together. P alone can complete it in 32 days. Both of them worked together for 8 days and then P left. The number of days Q will take to complete the remaining work is ?

A) 56 days B) 54 days
C) 60 days D) 64 days
 
Answer & Explanation Answer: D) 64 days

Explanation:

(P+Q)'s 1 day work = 1/24

P's 1 day work = 1/32

=> Q's 1 day work = 1/24 - 1/32 = 1/96

Work done by (P+Q) in 8 days = 8/24 = 1/3

Remainining work = 1 - 1/3 = 2/3

Time taken by Q to complete the remaining work = 2/3 x 96 = 64 days.

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6 301
Q:

A can complete 9/10 part of a work in 31 days. After that, with the help of B he can complete the remaining work in 4 days. In how many days will  A and B together can complete that work ?

A) 36 B) 40
C) 42 D) 38
 
Answer & Explanation Answer: B) 40

Explanation:

Remaining work = 1 - 9/10 = 1/10

=> A & B together completes 1/10 of work in 4 days

=> 1 work can completed in ------ ? days

Let it be x days

=>  

=> x = 40 days.

Hence, A & B together can complete the work in 40 days.

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