Answer: (A) 6.6 sec (B) 6.89 sec
<u>Step-by-step explanation:</u>
y = -16t² + 1700
1000 = -16t² + 1700
<u>-1700</u> <u> -1700 </u>
-700 = -16t²
<u> ÷-16 </u> <u>÷-16 </u>
43.75 = t²
√43.75 = √t²
6.6 = t
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y = -16t² + 1700
940 = -16t² + 1700
<u>-1700</u> <u> -1700 </u>
-760 = -16t²
<u> ÷-16 </u> <u>÷-16 </u>
47.5 = t²
√47.5 = √t²
6.89 = t
The two are perpendicular to each other because the two slopes are negative reciprocals
(Y2 - Y1) / (X2 - X1)
First slope:
( 1 - (-1)) / (-11 - (-6))
2/-5
Second slope:
(-13 - (-8)) / (-5 - (-3))
-5/-2 or 5/2
You know when two aliens are perpendicular when you multiply the two slopes and get -1 as the product
-2/5 X 5/2 = -1
Thus the two lines are perpendicular to each other.
So from what I understand, you would multiply 10m by 5m for the width to get 50m squared, and multiply the 50 by 2 to get 100m for both sides of the width for the pool. Next the length. Multiply 25m by 2.5m to get 62.5m squared. Once again, mutiply it by 2 for both side lengths of the pool to get 125m. Last, add 125m and 100m to get 225m for the concrete border of the pool.
We know that C is 385, so we can plug that in to get the equation 385=15n+85. To find the number of watches, we have to solve for n.
To do that we have to...
385=15n+85
First subtract both sides of the equal sign by 85 (because we need to do the opposite)
300=15n (because 85-85 is zero, so we eliminated that, and 385-85 is 300)
Now we divide both sides of the equal sign by 15 (again, opposites)
20=n (because 15n/15 leaves us with n since both 15s cancel out, and 300/15 is 20)
So the number of watches made were 20.
