Robert Bosch Time & Work Quiz-1

LCM of 24 , 20 and 15 = 120
total work = 120
efficiency of Rita = 120/24 = 5
efficiency of Gita = 120/20 = 6
efficiency of Rita = 120/15 = 8
difference = \frac{3800\times(8-6)}{9} = rs.400

Explanation:
Suppose B takes x days. Then ,
A takes 150x/100 days , i.e. 3x/2 days
=> 1/x+ 2/3x= 1/18
=> 5/3x= 1/18
=> 3x = 90
=> x= 30
Hence B takes 30 days

Explanation:

In the 1st day Anand does 1/7th of total work
similarly, Bithu does 1/8th work in the 2nd day
hence at d end of 3 days, work done = 1/7+1/8+1/6=73/168
remaining work = (168-73)/168 = 95/168
again after 6 days of work, remaining work is = (95-73)/168 = 22/168
and hence Anand completes the work on 7th day

Let Billy's time to complete one work = x days.

Then, Silly's time to complete one work = 4x days.

Since Billy takes 45 days less than Silly to build a wall.

i.e., 4x - x = 45 => x = 15 and 4x = 60.

Working together they will take \frac{1}{\frac{1}{5}+\frac{1}{60}}=12 days to build one wall. So, to build two such walls, 24 days will be required.

Answer: C

Explanation:
According to the question, 3 times Badal's daily work = (Abhishek + Chitra)'s daily work.
Add Badal's daily work to both sides.

=> 4 times Badal's daily work = (Abhishek + Badal + Chitra)'s daily work = 1/10.
=>Badal's daily work = 1/40 .... (1)

Also, 2 times Chitra's daily work = (Abhishek + Badal)'s daily work.
Add Chitra's daily work to both sides.
=>3 times Chitra's daily work = (Abhishek + Badal + Chitra)'s daily work = 1/10.
=>Chitra's daily work = 1/30 .... (2)

Now Abhishek's daily work = 1/10 — (1/40 + 1/30) = 1/24 ...(3)

Hence, Abhishek, Badal and Chitra can complete the project in 24, 40 and 30 days respectively.

Answer: A
Explanation:
Let the efficiency of Manish and Naman is x and y respectively. Then, according to the first condition;
Total amount of work = (x+ y) *12
If Manish had worked half as efficiently as she usually does, and naman had worked thrice as efficiently as he usually does
Total amount of work = (x/2 + 3y) 9
Both works should be equal,
So, (x+ y) 12= (x/2 + 3y) 9
On solving, x = 2y
Let Manish will take D days if he works alone;
Total work = xD = (x+ y) 12
Put x = 2y in the above equation;
2y D = (2y + y) 12
On solving, we get D = 18 days.
Hence, Manish will take 18 days to build a wall.

Answer: B
Explanation:
Let k be the part of work All three friends can do in one day
and x -10, x, y be the number of days for which they remained present. Then,
(x−10)k + xk = 23 and yk =13(2x−10)13y = 23 ⇒ 2x−10=2y⇒ x−5 =y
The required number of days = y−(x−10) = 5

Answer: B
Explanation: Priyanshu's 1 day work = 1/50. 5 days work = (5/50) = 1/10.
=>Remaining work = 1 - (1/10) = 9/10.
As Ashish completes 9/10 work in 30 days, so the work done by him in one day = 9/300. When they work together, the work done by them in one day = (1/50) + (9/300) = 1/20.
Hence, Number of days required by them working together = 20.

Answer: B
Explanation: Let Mohan's time to complete one Building = x days.
Then, Rishikesh's time to complete one Building = 4x days.
According to the Question,
Mohan takes 45 days less than Rishikesh to build a building.
i.e., 4x - x = 45 => x = 15 and 4x = 60.
Working together they will take \frac{1}{\frac{1}{15}+\frac{1}{60}}
days to build one building.
So, to build two such buildings, 24 days will be required.

Answer: A
Explanation: Let the whole painting be completed in x days.
Only Bipul remains from the start to the finish of the work. Bipul worked for x days.
Shekhar worked for 2 days and Vishal worked for (x-3) days.

\frac{2}{10}+\frac{x-3}{12}+\frac{x}{15} = 1
Hence, The wall will be painted in 7 days.