Elitmus Exam Numerical Ability Time and Work

If a group of some persons start working together. At the end of one day, one worker left the group. The day,when last worker lef,the work has completed. If all workers do same work together then how many days it will take to complete work...???

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let each person do the work on each day is 1unit.
let their are n person on first day.
workdone on first day =n*(work of each person)=>n*1=n;
on nextday =n-1;
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on last day work done=1;
total workdone=n+n-1+.........1=n(n+1)/2
let total work completed by all the persons working together is x days
in x days workdone by all the persons.........=n(n+1)/2;
so in 1 day workdone==n(n+1)/2x;----------1
and we knw that work done by all the persons in day=n;--------2;
so from eq1 and eq2;
n=n(n+1)/2x;
x=(n+1)/2;
9 years agoHelpfull: Yes(5) No(0)

for n number of workers answer will be n+1/2
10 years agoHelpfull: Yes(2) No(0)
ans-2 days
let us take there are 3 men and 1 day work of each person is 1/6.
so, 1st day work=1/6+1/6+1/6
=1/2
2nd day work(when one left)=1/6+1/6
=1/3
3rd day work(when one more left)=1/6
so, total work in 3 days =1/2+1/3+1/6=1
hence work is completed when last person lefts
so,when all 3 person working together the work will complete in 2 days(
1st day--1/2,2nd day--1/2)
10 years agoHelpfull: Yes(2) No(2)
n+(n-1)+(n-2)+....+2+1 = 1;

n(n+1)/2=1;

n=1;
10 years agoHelpfull: Yes(1) No(8)
???? ye kya hai bhai? itna to koi b kar lega.
10 years agoHelpfull: Yes(0) No(14)

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Find the profit percentage earned by the trader.

I. The loss incurred by the trader, when he sells at three-fourth the actual selling price is
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Mark a : if the question can be answered by using one of the statements alone, but cannot
be answered by using the other statement alone.
Mark b : if the question can be answered by using either statement alone.
Mark c : if the question can be answered by using both statements together, but cannot be
answered by using either statement alone.
Mark d : if the question cannot be answered even by using both the statements together. a,b,c,d are prime number. how many combintion of prime numbers can be possible such that the sum of two digit(a+b,a+c,a+d,....)..And the sum in increasing order are 2,4,6,8...

option-- 1 only 2 only 4 only more than 4