9514 1404 393
Answer:
3.61 seconds
Step-by-step explanation:
The bird starts 50 feet in the air, so will come down to a height of 40 feet after 3.61 seconds.
We want to solve h = 40.
40 = -16t^2 +55t +50
16t^2 -55t -10 = 0
t = (55 +√(55^2 -4(16)(-10)))/(2(16)) = (55 + √3665)/32 ≈ 3.61060
The bird will be 40 ft above the ground the first time after about 3.61 seconds.
Answer:
look at explanation
Step-by-step explanation:
To solve all of these questions you just need to scale. While scaling you can divide or multiply.
1. (divide by 4 to get unit rate)
unit rate =
2. If it takes one hour to travel 40 miles, then we don't have to scale or anything. We know , the answer is...
"It'll only take one hour to travel 40 miles. This is correct because the unit rate is . "
3. Knowing that the constant speed of the plane is , we can scale then add half of the unit rate to get our answer.
x 3 =
800 x 3 = 2400
then add half of unit rate which is
= 400
so, our answer is
4. <--- ( divided by 2)
( multiplied x 2.5) --->
To get an easier way to find the answer, if possible you can scale back farther than the 1 hour mark.
Elmer would take 2 and a half hours to ride 15 km.
5. The boys speed is . All we need to do is divide by 2.
= 4