Answer: 21120 feet.
Step-by-step explanation: We start with the fraction 1/180, found by putting 20 seconds over one hour. Then, we need to get the amount of miles the speed of sound travels in 20 seconds. We can use the fraction above as a ratio to get it. 720/1 x 1/180 = 4 miles. Then, we'll just do 4 times 5280, which is 21120.
You start out with 3*-2+2y=10
Simplify and you get 2y-6=10
Add 6 to both sides. 2y=16
Divide both sides by 2. Your answer is y=8.
Answer:
20
Step-by-step explanation:
In 12 years, the sum of their ages will be 24 more than it is now. The sum of their ages now is 61-24 = 37.
If Jennifer is 3 years older than Peter, we have ...
j + (j -3) = 37
2j = 40 . . . . . . add 3
j = 20 . . . . . . . divide by 2
Jennifer is now 20 years old.
_____
Peter is now 17 years old. In 12 years, they will be 29 and 32, so their ages will sum to 61.