A local hotel has 158 rooms. Due to a scouting event, the entire hotel booked except for two rooms. If the girls scouts are using three times as many rooms as the boy scouts, how many rooms are the boy scouts using?

39

Step-by-step explanation:

Let, total rooms girls booked be x and total rooms girls booked be y.

entire hotel was booked except two rooms.

so, total = 158-2 = 156

x+ y = 156

this is equation 1.

also, girls are using three times more room than boys.

so, y=3x

substituting y=3x in 1st equation,

x+ 3x = 156

or, 4x = 156

or, x= 156/4

x= 39