Answer :
For 1 hour they can complete 1/2 of the job together.
1 / ( t - 3 ) + 1 / t = 1/2
( t + t - 3 ) / (t ( t -3 )) = 1/2
( 2 t - 3 ) / ( t² - 3 t ) = 1/2
4 t - 6 = t² - 3 t
t² - 7 t + 6 = 0
t² - 6 t - t + 6 = 0
t ( t - 6 ) - ( t - 6 ) = 0
( t - 6 ) ( t - 1 ) = 0
t = 6 or t = 1 ( Carl: 1 - 3 = - 2 < 0 , not correct )
Answer: Jennifer can paint the room for 6 hours on her own.
1 / ( t - 3 ) + 1 / t = 1/2
( t + t - 3 ) / (t ( t -3 )) = 1/2
( 2 t - 3 ) / ( t² - 3 t ) = 1/2
4 t - 6 = t² - 3 t
t² - 7 t + 6 = 0
t² - 6 t - t + 6 = 0
t ( t - 6 ) - ( t - 6 ) = 0
( t - 6 ) ( t - 1 ) = 0
t = 6 or t = 1 ( Carl: 1 - 3 = - 2 < 0 , not correct )
Answer: Jennifer can paint the room for 6 hours on her own.