Elitmus Exam Numerical Ability Time and Work

a and b working seperately can do a piece of work in 9 and 15 days respt.if they work for a day alternately,with a beginning,then the work will be completed in how many days?

Read Solution (Total 2)

a's 1 day work = 1/9
b's 1 day work =1/15
when they work together simultaneously work done by them in two days = (1/9+1/15) = 8/45
so wok done in 10 days = 8/45*5 =40/45 = 8/9
so work left =1-8/9 = 1/9
now a's work in 1 day =1/9
so total no. of days = 10+1 = 11
7 years agoHelpfull: Yes(1) No(0)

LCM OF 9 AND 15=45 (TOTAL WORK TO BE DONE)
A 1 DAY WORK=5
B 1 DAY WORK=3
ALTERNATIVELY WORKING A AND B IN 2 days they will do 8 units of work
so in 10 days they will do 40 units of work
now only 5 units of work is left
and on 11th day its A turn to do work (A 1 DAY WORK IS 5)
SO work will be completed in 10+1=11days
7 years agoHelpfull: Yes(0) No(0)

Elitmus Other Question

a sum of money doubles itself in 4 years at c.i .it will amount to 8 times itself at the same rate of interest in how many years a's 2 days work is equal to b's 3 days work.if a can complete the work in 8 days then to complete the work b will take how many days?