Answer is Correct. She could have also subtracted 100 from both sides, then divided by .
Answer:
8
Step-by-step explanation:
The midpoint of AC is ...
B = (A +C)/2 = (-10 +14)/2 = 2
The midpoint of BC is ...
D = (B +C)/2 = (2 +14)/2 = 8
The midpoint of BC is 8.
Let
x--------> <span>the speed of the boat in mph
we know that
</span>going upstream the speed is x-7
<span>going downstream the speed is x+7
</span>
let the distance be d
<span>time to go upstream = d/(x-7) </span>
<span>time to go downstream = d/(x+7)
</span>
time going upstream is 3 times going downstream
so
<span>3d/(x+7) = d/(x-7) </span>
<span>divide by d </span>
<span>3/(x+7) = 1/(x-7) </span>
<span>3x-21 = x+7 </span>
<span>2x = 28 </span>
<span>x = 14
</span>
the answer is
<span>the speed of the boat in still water is 14 mph</span>
Multiply 5 by 9.8 to get the answer.
Please check the picture.
