math
posted by john .
john takes 3hours longer than andrew to peel 400 pounds of apples. if together they can peel 400pounds of apples in 8hours then how long would it take john if he is working alone.

math 
Reiny
Andrew's rate = 400/x
Johns rate = 400/(x+3)
combined rate = (400(x+3) + 400x)/(x(x+3)
= 400(2x+2)/(x(x+2))
400 / [400(2x+3)/(x(x+3) ] = 8
1/[2x+3)/(x(x+2)) ] = 8
x(x+3)/(2x+3) = 8
x^2+3x = 16x + 24
x^2  13x  24 = 0
x = (13 ±√265)/2
x = 14.64 hrs , ignoring the negative answer
check:
combined rate = 1/14.64 + 1/17.64 = .125
time at comined time = 1/.125 = 8 , Yeahh!
Andrew alone can do it in 14.65 hrs
John alone can do it in 17.65 hrs
Respond to this Question
Similar Questions

algebra
John takes 3 hours longer than Andrew to peel 400 pounds of apples. Together they take 8 hours. How long will it take John to peel 400 pounds by himself 
math
john and mary are working on a job together. if john does it alone, it will take him seven days, while mary can do it alone in five days. how long will it take them to do it together? 
Math
John takes 2 hours longer than Andrew to peel 400 pounds of apples. If together they can peel 400 pounds of apples in 7 hours, then how long would it take Andrew to peal the apples working alone? 
5th grade math
John picked 30 bags of apples on monday and sold them at his fruit stand for $3.45 each. The following week he picked and sold 6 more. How much money did John earn the 1 st week? 
math
Q1.The zoo uses 10 pounds of apples each day. How many pounds of apples should be on the weekly grocery list? 
Larkmead
John has a £10 note. Apples cost £4.95 per kg. does John have enough money to buy 1.9 kg of apples 
algebra
mary and jen peel 1lb of apple.if together they peeled 500 lbs of apple in 8 hours,then how long would it take each one working together? 
Math
John can paint a room in 3 hours. His apprentice, working alone, requires 6 hours to do the same job. How long would it take John and his apprentice, working together, to paint the room if they continue to work at the given rates? 
Math
A store has apples on sale for $3.00 for 2 pounds. How many pounds of apples can you buy for $9.00? 
Algebra
John takes one hour more than Rikki to rake the leaves from their yard in the fall. If the two work together, they can rake the leaves in 2 hours. How long does it take John, working alone, to rake the leaves?