P completes \(\frac{1}{3}\) part of a work in 15 days and Q completes the remaining work in 45 days. In how many days can they together finish the same work?

This question was previously asked in
CRPF Constable Technical Tradesman Official Paper (Held On: 01 July, 2023 Shift 2)
View all CRPF Constable Papers >
  1. 27 days
  2. 30 days
  3. 21 days
  4. 25 days

Answer (Detailed Solution Below)

Option 1 : 27 days
Free
General Science for All Railway Exams Mock Test
2.1 Lakh Users
20 Questions 20 Marks 15 Mins

Detailed Solution

Download Solution PDF

Given:

P completes (1/3) of the work in 15 days.

Q completes the remaining work (2/3) in 45 days.

Formula used:

Work done per day = Efficiency

LCM method: Total work = LCM of individual work durations.

Calculation:

P completes (1/3) of work in 15 days, so full work will take:

Total work days for P = 15 × 3 = 45 days

Q completes (2/3) of work in 45 days, so full work will take:

Total work days for Q = (45 × 3) / 2 = 67.5 days

LCM of (45, 67.5) = 135 (Assuming work units)

Efficiency of P = 135 / 45 = 3 units/day

Efficiency of Q = 135 / 67.5 = 2 units/day

Total efficiency of (P + Q) = 3 + 2 = 5 units/day

Time required to complete full work = 135 / 5

= 27 days

∴ P and Q together can complete the work in 27 days.

Latest CRPF Constable Updates

Last updated on Jan 23, 2025

-> The CRPF Constable Scorecard & Cut Off have been released.

-> The PET/PST, Document Verification, and Medical Examination was conducted from 18th November 2024 onwards.

-> The written exam was conducted from 1st to 12th July 2023.

-> The CRPF Constable Notification (2023) was released for 9212 vacancies.

-> The selection process includes a Computer Based Test, Physical Standards Test (PST), Physical Efficiency Test (PET), Trade Test, Document Verification, and  Medical Examination.

->  To prepare for the exam practice using CRPF Constable Previous Year Papers. Also, attempt CRPF Constable Mock Test.

More Pipe and Cistern Questions

More Time and Work Questions

Get Free Access Now
Hot Links: teen patti lucky teen patti master 2024 teen patti classic teen patti real cash game