9514 1404 393
Answer:
21.25 seconds
Step-by-step explanation:
In miles per second, the speed of the jet is ...
(720 mi/h)/(3600 s/h) = 1/5 mi/s
The speed of the sound is the same:
(1 mi)/(5 s) = 1/5 mi/s
Then the rate of closure between the airplane and the sound is ...
(1/5 mi/s) +(1/5 mi/s) = 2/5 mi/s
To find the time required to close a gap of 8 1/2 miles, we can use the relation ...
time = distance/speed
time = (8.5 mi)/(0.4 mi/s) = 21.25 s
The pilot will hear the thunder 21.25 seconds after the flash.
Answer:
B
Step-by-step explanation:
A number increased by 7 means, 7 was added to the number and the result is 15
27.
Volume = length*width*height
So 3*3*3=27
Answer: a = -5
Step-by-step explanation:
First, open up the brackets, and solve it
-12a -42 = -22 -8a. (-6 x 2a, and -6 x 7)
bring the -8a to the left side, so that all the a’s are together
-12a -42 + 8a = -22 (add -42 on both sides like we did with -8a)
-12a + 8a = -22 + 42
solve
-4a = 20
divide -4 on both sides
a = -5
