Anand finishes a work in 7 days, Bittu finishes the same job in 8 days and Chandu in 6 days. They take turns to finish the work. Anand on the first day, Bittu on the second and Chandu on the third day and then Anand again and so on. On which day will the work get over?
In the 1st day Anand does 1/7th of total work
similarly, Bithu does 1/8th work in the 2nd day
hence at d end of 3 days, work done = 1/7+1/8+1/6=73/168
remaining work = (168-73)/168 = 95/168
again after 6 days of work, remaining work is = (95-73)/168 = 22/168
and hence Anand completes the work on 7th day
Susan can type 10 pages in 5 minutes. Mary can type 5 pages in 10 minutes. Working together, how many pages can they type in 30 minutes?
(30/5=6; 6*10=60; Susan will type 60 pages in 30 min. 30/10=3; 5*3=15; Mary will type 15 pages in 30 min. 60+15=75)
A can do a certain work in 12 days. B is 60% more efficient than A. How many days does B alone take to do the same job?
Ratio of time taken by A&B=160:100 =8:5
Running at the same constant rate, 6 identical machines can produce a total of 270 bottles per minute. At this rate, how many bottles could 10 such machines produce in 4 minutes?
Let the required number of bottles be x.
More machines, More bottles (Direct Proportion)
More minutes, More bottles (Direct Proportion)
Machines 6: 10
Time (in minutes) 1: 4 } : :270 : x
=> 6 x 1 x x = 10 x 4 x 270
= x = (10 x 4 x 270)/6 = x = 1800.
If a light flashes every 6 seconds, how many times will it flash in ¾ of an hour?
There are 60 minutes in an hour.
In ¾ of an hour is (60 * ¾) minutes = 45 minutes.
In ¾ of an hour is (60 * 45) seconds = 2700 seconds.
Light flash in 2700 seconds = 2700/6
= 450 times.
The count start after the first flash, the light will flashes 451 times in ¾ of an hour.
X can do ¼ of a work in 10 days, Y can do 40% of work in 40 days and Z can do 1/3 of work in 13 days. Who will complete the work first?
Whole work will be done by X in 10*4=40 days.
A and B weave a carpet in 10 days and 15 days respectively. They begin to work together but B leaves after 2 days. In what time will A complete the remaining work?
1 monkey takes 3 min to eat 1 banana. How much time will 10 monkeys take to eat 10 bananas?
Answer is 3 minutes only, because each will eat simultaneously 10 bananas for 3 minutes.
A contractor agreeing to finish a work in 150 days, employed 75 men each working 8 hours daily. After 90 days, only 2/7 of the work was completed. Increasing the number of men by ________ each working now for 10 hours daily, the work can be completed in time.
One day’s work = 2 / (7 * 90)
One hour’s work = 2 / (7 * 90 * 8)
One man’s work = 2 / (7 * 90 * 8 * 75)
The remaining work (5/7) has to be completed within 60 days, because
the total number of days allotted for the project is 150 days.
So we get the equation
(2 * 10 * x * 60) / (7 * 90 * 8 * 75) = 5/7 where x is the number of
men working after the 90th day.
We get x = 225
Since we have 75 men already, it is enough to add only 150 men.
A tank is filled in 5 hours by three pipes A, B and C. The pipe C is twice as fast as B and B is twice as fast as A. How much time will pipe A alone take to fill the tank?
