Question 445103
(1/24)+(1/X)=1/15
(X+24)/24X=1/15
24X=15(X+24)
24X=15X+360
24X-15X=360
9X=360
X=360/9
X=40 MINUTES FOR THE BROTHER WORKING ALONE.
PROOF:
1/24+1/40=1/15
(40+24)/24*40=1/15
64/960=1/15
1/15=1/15