If Rafi and Suman together can complete a job in 12 days. If Rafi alone can finish the job in 20 days, in how many days can Suman alone complete the work?
A
25 days
B
60 days
C
45 days
D
30 days
উত্তরের বিবরণ
Question: If Rafi and Suman together can complete a job in 12 days. If Rafi alone can finish the job in 20 days, in how many days can Suman alone complete the work?
Solution:
Rafi and Suman together can complete a piece of work in 12 days
Rafi and Suman together can complete in 1 day = 1/12
Rafi alone in 20 days
Rafi alone in one day = 1/20
∴ Suman complete in one day = (1/12) - (1/20)
= (5 - 3)/60
= 2/60
= 1/30
∴ Suman can complete the work in 30 days
0
Updated: 2 months ago
P is 25% more efficient than Q. How much time will they, working together, take to complete a job which Q alone could have done in 27 days?
Created: 1 month ago
A
8 days
B
15 days
C
18 days
D
12 days
Question: P is 25% more efficient than Q. How much time will they, working together, take to complete a job which Q alone could have done in 27 days?
Solution:
P, Q এর থেকে 25% বেশি দক্ষ।
⇒ P : Q = 125 : 100 = 5 : 4
Q এক দিনে কাজ করে = 4 ইউনিট
P এক দিনে কাজ করে = 5 ইউনিট
মোট কাজ = Q এর দৈনিক কাজ × Q এর দিন
= 4 × 27 = 108 ইউনিট
একসাথে এক দিনে কাজ করে = 5 + 4 = 9 ইউনিট
তাহলে কাজ শেষ করতে সময় লাগবে = 108 ÷ 9 দিন
= 12 দিন
সুতরাং, P এবং Q একত্রে কাজটি শেষ করতে 12 দিন সময় নেবে।
0
Updated: 1 month ago
Two pipes, A and B, can fill a tank in 37.5 minutes and 45 minutes. If both pipes are open, after how many minutes should pipe B be closed to fill the tank in half an hour?
Created: 3 weeks ago
A
5 minutes
B
9 minutes
C
10 minutes
D
15 minutes
Question: Two pipes, A and B, can fill a tank in 37.5 minutes and 45 minutes. If both pipes are open, after how many minutes should pipe B be closed to fill the tank in half an hour?
Solution:
নল A দ্বারা 37.5 মিনিটে পূর্ণ হয় 1 অংশ
∴ 1 মিনিটে পূর্ণ হয় = (1/37.5) অংশ
∴ 30 মিনিটে পূর্ণ হয় = 30/37.5 = 300/375 = 4/5 অংশ
∴ পূর্ণ হওয়ার বাকি থাকে = 1 - (4/5)
= (5 - 4)/5
= 1/5 অংশ
B নল দ্বারা ,
1 অংশ পূর্ণ হতে সময় লাগে = 45 মিনিট
∴ 1/5 অংশ পূর্ণ হতে সময় লাগে = 45 × (1/5) = 9 মিনিট
∴ B নলটি 9 মিনিট পর বন্ধ করলে ট্যাংকটি 30 মিনিটে পূর্ণ হবে।
Shortcut:
(30/37.5) + (x/45) = 1 (whole)
⇒ 0.8 + (x/45) = 1
⇒ x/45 = 1 - 0.8 = 0.2
⇒ x = 0.2 × 45 = 9
0
Updated: 3 weeks ago
Three mechanics A, B, and C can manufacture 120 units in 12, 20, and 30 hours respectively. What is the ratio of the time taken by A alone to complete the work to the time taken by all three working together to complete the same work?
Created: 2 months ago
A
5 : 2
B
4 : 3
C
3 : 1
D
2 : 1
Question: Three mechanics A, B, and C can manufacture 120 units in 12, 20, and 30 hours respectively. What is the ratio of the time taken by A alone to complete the work to the time taken by all three working together to complete the same work?
Solution:
(A + B + C) together can do in 1 hour = (1/12) + (1/20) + (1/30)
= (5 + 3 + 2)/60
= 10/60
= 1/6
So, working together they complete the work in 6 hours.
And A alone takes 12 hours.
∴ Ratio of the time taken by A and (A + B + C) =12 : 6 = 2 : 1
0
Updated: 2 months ago
