Answer:
Speed of boat in still water is 26km/hr
Step-by-step explanation:
Let the speed of boat in still water be x and speed of stream by y.
Speed at which it went upstream would be (x-y) and the speed at which it went downstream would be (x+y). According to question x+y=24 and x-y=28. x=26 and y=-2.
Answer:
about 81 years
Step-by-step explanation:
A graphing calculator can give you the answer easily.
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You can solve the problem algebraically by putting in the given number and solving for t.
30000 = 32000/(1 +12.8e^(-.065t))
12.8e^(-.065t) = (32000/30000) -1 = 1/15
e^(-.065t) = 1/(15·12.8) = 1/192 . . . . . divide by 12.8
-0.065t = ln(1/192) ≈ -5.257 . . . . . . take the natural log
t = -5.257/-0.065 ≈ 80.88 . . . . . . . .divide by the coefficient of t
It will take about 81 years for the number of trees to reach 30,000.
<span>each missing number is the square of half the coefficient of the 1st order term</span><span>
(5/2)² = 25/4 </span>