Answer:
300 doors.
Step-by-step explanation:
1.5 minutes for 1 door.
7.5 hours for 300 doors.
7.5 hours = 450 minutes.

Difference of a number and 17: x - 17
eight times that = 8(x - 17)
8(x - 17) = 30
divide both sides by 8
x - 17 = 30/8
x = 30/8 + 17 which is 20.75
Answer:
.571
Step-by-step explanation:
We need to find the total number of boys
11+5+4 = 20
And the total number of students
11+7+5+4+4+4 = 35
The Probability that the student is a boy is boy/total
P (boy) = boy/total
= 20/35
=4/7
=.571428571
to 3 decimal places
=.571
Answer:
-9
Step-by-step explanation:
-2x + 3 = -x + 12
move -x over by adding
-x + 3 = 12
move the 3 over by subtracting
-x = 9
divide by - to get the x positive
x = -9