<PRE><B>Question 252650</B>
Let x=amount of time it takes Deng working alone
Then Deng works at the rate of 1/x uniform/hr

Deng and Dolly together work at the rate of 1/2 uniform/hour
Dolly, working alone, works at the rate of 1/5 uniform/hr

So, our equation to solve is:
1/x + 1/5= 1/2  multiply each term by 10x
10+2x=5x  subtract 2x from each side
10+2x-2x=5x-2x
3x=10
x=3 1/3 hours=10/3 hours----Amount of time needed for Deng to do the job working alone

CK

1/5 +(1/10/3)=1/2
1/5 +3/10=1/2
2/10+3/10=1/2
1/2=1/2

Hope this helps---ptaylor</PRE>