Homework Help: maths

Posted by simranpreet on Monday, December 3, 2012 at 6:57am.

300 men were engaged to complete a job in a certain number of days. but due to another assignment fifteen men dropped the second day, fifteen more men dropped the third days and so on .if takes fifteen more days to finish the work now.find the number of days in which the work was completed. please hellllllppppp.

maths - Reiny, Monday, December 3, 2012 at 9:08am
The number of man-hours that were used were

300 + 285 + 270 + 255 + ... + 15 + 0
Since we can't count the + 0 , (nobody worked that day) ,
we need the number of terms of
300+285 + ... + 15

the left side is an AS where a = 300 , d = -15 , n = ?

when the last term is 15
15 = a + d(n-1)
15 = 300 - 15(n-1)
15 = 300-15m + 15
15n = 300
n = 20

Answer this Question

Related Questions

airthmetic progression - 300 men wre engaged to complete a job in acertain ...
maths, proportion - twelve men take 6 hours to finish a piece of work. after the...
math - Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do in 2...
math - If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do ...
Math - If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do ...
MATHS - 5 women complete half a job in 15 days. How long would it take 3 women ...
arithmetic - Three men are working together can finish a house repair job in 10 ...
math - Alex takes 3 hours longer to complete a certain job than Barry does. If ...
work - b)5 men can do equal amount of work as 8 women. If 3 men and 5 women ...
Math - If a job can be completed by 8 people in 6 days, how many days does it ...

For Further Reading

First Name:
School Subject:
Answer: