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>
Answer:
80n - 64p + 72
Step-by-step explanation:
8(10n) + 8(-8p) + 8(9)
80n - 64p + 72
Answer:
x + 5y = 0
Step-by-step explanation:
y = mx + b
y = -1/5 x + b
1 = -1/5 (-5) + b
1 = 1 + b
b = 0
y = -1/5 x
5y = -x
x + 5y = 0
Answer:
x= 45
Step-by-step explanation:
x= -15*-3
x= 45
