Question
The average number of books of Biology, Chemistry and
Physics in a book shop is 360. Biology books are 180 more than the average number of Chemistry and Physics books. The number of Physics books is 180 less than the average number of Biology and Chemistry books. What is the number of chemistry books in the shop?Solution
: Let the number of biology, chemistry and physics books be B, C and P. B+C+P =360×3=1080 B+C+P=1080   … (1) Biology books =180+Average number of (C and P) B=180+(C+P)/2 2B=360+C+P 2B-C-P=360     … (2) Physics books =Average of (B+C)/2 -180 P=B+C)/2 -180 2P=B+C-360 B+C-2P=360    … (3) Adding Equation (1) and (3) and subtracting (2) ... (B+C+P) + B+C-2P -2B+C+P=1080+360-360 3C=1080 C=360.
- Vikas does 65% of a job in 39 days, while Suman does 40% in 40 days. Vikas worked for 18 days and left. Calculate how many days Suman would need to wrap up...
Komal and Seema individually can complete a task in ‘5a’ hours and ‘7a’ hours respectively. If they together can complete (4/5)th of the work in...
'A' and 'B' alone can complete a work in 9 days and 18 days, respectively. Find the time taken by them to complete the work if they work on alternate da...
Efficiency of A is 25% more than B and B takes 30 days to complete a piece of work. A started the work alone and then B joined him 4 days before actual ...
A group of workers was put on a job. From the second day onwards, 1 worker left work everyday. If no worker was left when 52% of the work gets complete...
Ajay, Bablu and Chirag can complete a certain work in 21, 28 and 15 days respectively. Ajay and Chirag started the work while Bablu joined them after 5 ...
A can complete a job in 20 hours. B alone can complete the same job in 15 hrs. A work for 9 hrs and then the remaining job is completed by B. How many h...
Ananya and Riya can complete a task in 20 hours and 40 hours respectively. Ananya works alone for 10 hours and then Riya finishes the remaining task. Ho...
- Alex and Ben can complete a job individually in 14 days and 21 days, respectively. If they take turns to work one day each, beginning with Alex, how long w...
- Pipes X and Y can fill a tank in 45 minutes and 60 minutes respectively. Another pipe Z can empty the tank in 1 hour 30 minutes. If X and Z are opened firs...
Relevant for Exams:
