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# Nikola and Ilia finished their work for 10 days. Nikola finished the work for 15 days alone. For how much time did Ilia finished the work al

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Nikola and Ilia finished their work for 10 days. Nikola finished the work for 15 days alone. For how much time did Ilia finished the work alone?

Mihail  Feb 11, 2015

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Thanks Alan,

I am going to play with this one as well because I  need the practice.

Nikola does   $$\frac{1}{15}$$   of a unit of work in a day.

Nikola and llia together do  $$\frac{1}{10}$$  of a unit of work in a day

so llia must do  $$\frac{1}{10}-\frac{1}{15} = \frac{3}{30}-\frac{2}{30}= \frac{1}{30}$$

So by herself llia would take 30 days to complete the task

Melody  Feb 11, 2015
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this question is kind of confusing me ...was their any other info given?

rosala  Feb 11, 2015
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Rosala, I think this question could be rephrased as follows:

Nikola can complete N units of work on her own in 15 days.

Nikola and Ilia together can complete N units of work in 10 days.

In how many days could Ilia complete N units of work on her own?

Note that Nikola works at a rate of N/15 units of work per day.

Assume Ilia works at a rate of N/T units of work a day.  The idea is to find the value of T.

(N is unknown of course.)

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Alan  Feb 11, 2015
#3
+92623
+13

Thanks Alan,

I am going to play with this one as well because I  need the practice.

Nikola does   $$\frac{1}{15}$$   of a unit of work in a day.

Nikola and llia together do  $$\frac{1}{10}$$  of a unit of work in a day

so llia must do  $$\frac{1}{10}-\frac{1}{15} = \frac{3}{30}-\frac{2}{30}= \frac{1}{30}$$

So by herself llia would take 30 days to complete the task

Melody  Feb 11, 2015