All Exams Test series for 1 year @ ₹349 only
Question

A and B working together can complete a job in 30 days. The ratio of their efficiencies is 3 : 2. In how many days can the faster person complete the job?

The correct answer is

50

Understanding Work and Efficiency Ratio

This problem requires calculating the time the most efficient person takes to finish a job, given their combined work duration and efficiency ratio.

Calculating Individual Efficiencies

Let the efficiencies of person A and person B be $E_A$ and $E_B$. The ratio $E_A : E_B$ is given as 3:2.

  • Assume $E_A = 3x$
  • Assume $E_B = 2x

The combined efficiency is $E_{Total} = E_A + E_B = 3x + 2x = 5x$.

Calculating Total Work

The total work ($W$) equals the combined efficiency multiplied by the time they took working together.

Given time together = 30 days:

$W = E_{Total} \times 30$

$W = (5x) \times 30 = 150x$ units of work.

Finding Time for the Faster Person

The faster person has the higher efficiency. Here, A (with $3x$ efficiency) is faster than B (with $2x$ efficiency).

The time taken by the faster person (A) is:

$Time_A = \frac{W}{E_A}$

$Time_A = \frac{150x}{3x}$

$Time_A = 50$ days.

The faster person can complete the job in 50 days.

Was this answer helpful?

Important Questions from Work Efficiency

  1. A takes 15 days to complete \(\frac{5}{7} \)  of a work. With the help of B, they finish the whole work in 12 days. In how many days, B alone will complete the same work

  2. A alone can complete a work in 14 days and B alone can complete the same work in 21 days. A and B start the work together but A leaves the work after 4 days of the starting of work. In how many days B will complete the remaining work?

  3. For completing a certain work, A is 50% less efficient than B and B is 50% more efficient than C. Working together A, B and C can complete the work in 48 days. A alone can complete the same work in:

  4. 30 persons can do a piece of work in 24 days. How many more persons are required to complete the work in 20 days?

  5. X is twice as good as workman as Y. Together, they finish the work in 18 days. In how many days can it be done by each separately?

Need Expert Advice?

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App