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