Answer:
Step-by-step explanation:
Let he speed of the boat on the lake is x.
<u>Considering the speed of the current it will take him:</u>
- 22.5/(x + 6) + 22.5/(x - 6) = 9
- 2.5 / (x + 6) + 2.5 / (x - 6) = 1
- 2.5(x - 6 + x + 6) = (x + 6)(x - 6)
- 2.5*2x = x² - 36
- x² - 5x - 36 = 0
- x = (5 ± √(5² + 4*36))/2 = (5 ± 13) / 2
- x = (5 + 13)/2 = 9 mph (negative root is discarded as the speed should be positive)
Answer:
√
28
Rewrite
28
as
2
2
⋅
7
.
Tap for more steps...
√
2
2
⋅
7
Pull terms out from under the radical.
2
√
7
The result can be shown in both exact and decimal forms.
Exact Form:
2
√
7
Decimal Form:
5.29150262
…
Step-by-step explanation:
Here we would use the idea that the post and its shadow form a triangle and the tree and its shadow form a triangle and the side lengths of these two triangles are of the same ratio, ie. if the height of the tree is given by h then:
5/8 = h/48
h = 48*(5/8)
h = 6*5 = 30
Thus the tree is 30 ft tall
It is A. 6.9 x 10^5 Because
<span><span>2.3<span>(<span>10<span>−3</span></span>)</span></span><span>(<span>3<span>(<span>108</span>)</span></span>)</span></span><span>=<span><span>2.3<span>(<span>11000</span>)</span></span><span>(<span>3<span>(<span>108</span>)</span></span>)</span></span></span><span>=<span>0.0023<span>(<span>3<span>(<span>108</span>)</span></span>)</span></span></span><span>=<span><span>0.0023<span>(3)</span></span><span>(100000000)</span></span></span><span>=<span><span>(0.0023)</span><span>(300000000)</span></span></span><span>=<span>690000
then 6.9*10^5 = 690000</span></span>
