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।

Question: A man completes 2/5 of a work in 8 days. If his work rate is doubled, how many more days will it take him to finish the remaining work?

Solution:
2/5 of the work is done in = 8 days
∴ full work is done in = (8 × 5)/2 days
= 20 days

∴ His daily work rate = 1/20 per day

If his work rate is doubled, his new daily work rate is,
= (1/20) × 2 = 1/10 per day

Remaining portion of the job = 1 - (2/5)
= 3/5

Now,
1/10 work is done in = 1 day
∴ 3/5 work is done in = (3/5) ÷ (1/10) days
= (3/5) × 10
 = 6 days

Therefore, it will take him 6 more days to finish the job.