GMAT Exam

a man build 1/8th of a wall everyday.Out of the wall built every day 20% falls each day (including last day). In How many days wall be completed.
Explained Please!!!!!

Read Solution (Total 4)

let no days taken to complete to built a wall be x
x*(1/8)-x*(1/40)=1
So x=10 days
11 years agoHelpfull: Yes(5) No(0)

let no. of days to complete the wall be x.
then the equation is-
80/100(x*1/8)=1
so x=10days
11 years agoHelpfull: Yes(2) No(2)
1/8 is 12.5%. 20% of it is 1/5 of it so that's 2.5% So in a day he completes 10% so he needs 10 days.
11 years agoHelpfull: Yes(1) No(0)
effective buil in every day 1/8-1/40=1/10 so ans will be 9.8 days because last day he will hav to complete only 1/10 part
11 years agoHelpfull: Yes(1) No(0)

GMAT Other Question

The eigen values of a matrix A= ⌊■(cos⁡θ&-sin⁡θ@sin⁡θ&cos⁡θ )⌋ A man starts a piece of work. Starting from 2nd day onwards,everyday a new man joins. With every man joining the work that each man can do per day doubles.The work is completed in 5 days.
On which day they would have completed the work if the work each man can do per day remained constant.
Please Explain!!!