6 Views

Question : P is thrice as good as a workman as Q and therefore can finish a work in 40 days less than Q. In how many days can they together complete the same work?

Option 1: 20 days

Option 2: 15 days

Option 3: 22.5 days

Option 4: 18 days


Team Careers360 20th Jan, 2024
Answer (1)
Team Careers360 23rd Jan, 2024

Correct Answer: 15 days


Solution : Let Q finish the work in $D$ days then P will finish the same work in $(D - 40)$ days.
So, 1-day work (efficiency) of Q = $\frac{1}{D}$ 
and 1-day work (efficiency) of P = $\frac{1}{D - 40}$
According to the question
⇒ $\frac{1}{D - 40}$ = 3 × $\frac{1}{D}$
⇒ D = 3(D – 40)
⇒ D = 60
⇒ Q's time = 60 days
⇒ P’s time = 60 − 40 = 20 days
1-day work of P and Q together = P’s 1-day work + Q’s 1-day work 
$=\frac{1}{D – 40}$ + $\frac{1}{D}=\frac{1}{20} + \frac{1}{60} = \frac{4}{60}= \frac{1}{15}$
So, time taken by P and Q together = $\frac{1}{\frac{1}{15}}$ = 15 days
Hence, the correct answer is 15 days.

Know More About

Related Questions

Amity Online MBA
Apply
Apply for an Online MBA from Amity Online.
Manipal Online M.Com Admissions
Apply
Apply for Online M.Com from Manipal University
View All Application Forms

Download the Careers360 App on your Android phone

Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile

150M+ Students
30,000+ Colleges
500+ Exams
1500+ E-books