27/40+(27-x)/60= 1
0.675+(27-x)/60= 1
(27-x)/60= 1-0.675
(27-x)/60=0.325
27-x=0.325*60
27-x= 19.5
x=27- 19.5
x=7.5
2. Solution: Room X in the dormitory represents (2X+ 12) people.
3X-2=2X+ 12
x= 14
3、( 1- 1/2)*( 1- 1/3)*( 1- 1/4)*200
= ( 1/2)*(2/3)*(4/3)*200
=( 1/4)*200
=50 meters