Question 910220
See
 http://www.algebra.com/algebra/homework/Rate-of-work-word-problems/Rate-of-work-word-problems.faq.question.910120.html
1/x+1/(x+15)=1/22
(22*x*(x+15))/x+(22*x*(x+15))/(x+15)=(22*x*(x+15))/22
(22*(x+15))+22*x=x*(x+15)
22*x+330+22*x=x^2+15*x
44*x+330=x^2+15*x
x^2-29*x-330=0
Positive useful answer:
x=14.5+23.2432786
One answer is x=37.7
x+15=15+37.7
x+15=52.7