Question:
A and B together do a work in 12 days; B alone does it in 20 days. In how many days can A alone do it?
A and B together do a work in 12 days; B alone does it in 20 days. In how many days can A alone do it?
Updated On: Jul 10, 2026
- 30 days
- 24 days
- 15 days
- 36 days
Show Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Step 1: A's one day work \(= \dfrac{1}{12}-\dfrac{1}{20} = \dfrac{5-3}{60} = \dfrac{2}{60} = \dfrac{1}{30}\).
Step 2: So A alone takes 30 days.
Step 2: So A alone takes 30 days.
Quick Tip: Subtract the known rate from the combined rate to isolate the other worker.
Was this answer helpful?
0
0
Top ATMA Quantitative Aptitude Questions
- If A and B can do a piece of work in 10 days and B can do it in 15 days then A can do the same work in
- If Ravi and Gopi can workout a problem in 20 min and 15 min individually then together can work out in
- If 40 people can complete a project in 100 days then 10 people complete the same project in
- The mean of 10 numbers is 152 then their sum is
- If the average of first 10 natural numbers is 5.5 and 3 is subtracted from each number then the average will be
View More Questions
Top ATMA Time and Work Questions
- If A and B can do a piece of work in 10 days and B can do it in 15 days then A can do the same work in
- If Ravi and Gopi can workout a problem in 20 min and 15 min individually then together can work out in
- If 40 people can complete a project in 100 days then 10 people complete the same project in
- Ten men can paint a room in 3 hours. How many hours would 5 men take to paint the room, if they work at the same rate?
- A boy eats 12 burgers in an hour. How many burgers will 8 boys eat in 20 minutes?
View More Questions
Top ATMA Questions
- Read the passage and answer the questions that follow.
How Facebook is changing the way we consume news
Greg Marra’s team designs the code that drives Facebook’s News Feed – the stream of updates, photographs, videos and stories that users see. The 26-year-old Facebook engineer is also fast becoming one of the most influential people in the news business. Facebook now has a fifth of the world – about 1.3 billion people – logging on at least monthly. It drives up to 20 percent of traffic to news sites, according to figures from the analytics company SimpleReach. On mobile devices, the fastest-growing source of readers, the percentage is even higher, SimpleReach says.
About 30 percent of adults in the U.S. get their news on Facebook, according to a study from the Pew Research Center. Though other services, like Twitter and Google News, can also exert a large influence, Facebook is at the forefront of a fundamental change in how people consume journalism. Most readers now come to news not through the print editions of newspapers and magazines or their home pages online, but through social media and search engines driven by an algorithm, a mathematical formula that predicts what users might want to read.
It is a world of fragments, filtered by code and delivered on demand. For news organizations, said Cory Haik, senior editor for digital news at The Washington Post, the shift represents “the great unbundling” of journalism. “People won’t type in washingtonpost.com anymore,” Ms. Haik said. “It’s search and social.”
In an interview at Facebook’s sprawling headquarters here, Mr. Marra said he does not think too much about his impact on journalism. “We try to explicitly view ourselves as not editors,” he said. “We don’t want to have editorial judgment over the content that’s in your feed. You’ve made your friends, you’ve connected to the pages that you want to connect to and you’re the best decider for the things that you care about.”Mr. Marra said, “We’re saying ‘We think that of all the stuff you’ve connected yourself to, this is the stuff you’d be most interested in reading.’”
Roughly once a week, he and his team of about 16 adjust the complex computer code that decides what to show a user when he or she first logs on to Facebook. The code is based on “thousands and thousands” of metrics, Mr. Marra said, including what device a user is on, how many comments or likes a story has received and how long readers spend on an article. The goal is to identify what users most enjoy, and its results vary around the world. In India, he said, people tend to share what the company calls the ABCDs: astrology, Bollywood, cricket and divinity. - Fill in the blank with the correct Article:
______ Newton is a great scientist. - Fill in the blank with the correct Article:
_________ frozen snow crushed under the wheels of our car. - Fill in the blank with the correct Article:
_______ town is famous for its hot springs. - Fill in the blank with the correct Article:
We decided to go boating on __________ Dal lake
View More Questions