Questions on Word Problems: Rate of work, PAINTING, Pool Filling answered by real tutors!

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Question 150509This question is from textbook
: working together, alice and betty can do a certain job in 4 1/3 days. but alice fell ill after 2 days of working and betty finished the job continuing to work alone in 6 3/4 more days. how long would it take each to do the job if each of them worked alone?This question is from textbook
: working together, alice and betty can do a certain job in 4 1/3 days. but alice fell ill after 2 days of working and betty finished the job continuing to work alone in 6 3/4 more days. how long would it take each to do the job if each of them worked alone?
Answer by ankor@dixie-net.com(4484) About Me  (Show Source):
You can put this solution on YOUR website!
working together, alice and betty can do a certain job in 4 1/3 days. but alice fell ill after 2 days of working and betty finished the job continuing to work alone in 6 3/4 more days. how long would it take each to do the job if each of them worked alone?
:
Let a = time required by Alice working alone
Let b = time required by Betty alone
Let the completed job = 1
:
equation when they both work 41/3 day
4.33/a + 4.33/b = 1
Multiply equation by 3 give us integers to work with
13/a + 13/b = 3
:
Equation when one got sick; (b worked a total of 2+6.75 = 8.75
2/a + 8.75/b = 1
Multiply equation by 6.5
13/a + 56.875/b = 6.5
:
Use elimination here:
13/a + 56.875/b = 6.5
13/a + 13/b = 3
-------------------------------subtraction eliminates a, find b
43.875/b = 3.5
3.5b = 43.875
b = 43.75/3.5
b = 12.5357 days for Betty alone
:
Use 13/a + 13/b = 3, substitute for b and find a
13/a + 13/12.5357 = 3
13/a + 1.037 = 3
13/a = 3 - 1.037
13/a = 1.963
1.963a = 13
a = 13/1.963
a = 6.6225 days for Alice alone
;
:
To check solutions, use 2/a + 8.75/b = 1, substituting for a and b:
2/6.6225 + 8.75/12.5357 = 1
.302 + .698 = 1; confirms our solution