Question 249507
Let c=time it takes cliff to paint a room. Let n=time it takes norm.
n=c-3
Cliff can do 1/c of the job in 1 hr
Norm can do 1/(c-3) of the job in 1 hour
together they can do 1/4 the job in 1 hr. 
1/(c-3) + 1/c = 1/4 
4c+4(c-3)=c(c-3) multiply each side by 4c(c-3) to eliminate fractions.
4c+4c-12=c^2-3c
c^2-11c+12=0
c=9.77 hrs
.
Ed
.
 *[invoke quadratic "x", 1, -11, 12]