Answer:
if repetition is allowed, 
if repetition is not allowed.
Step-by-step explanation:
For the first case, we have a choice of 26 letters <em>each step of the way. </em>For each of the 26 letters we can pick for the first slot, we can pick 26 for the second, and for each of <em>those</em> 26, we can pick between 26 again for our third slot, and well, you get the idea. Each step, we're multiplying the number of possible passwords by 26, so for a four-letter password, that comes out to 26 × 26 × 26 × 26 = possible passwords.
If repetition is <em>not </em>allowed, we're slowly going to deplete our supply of letters. We still get 26 to choose from for the first letter, but once we've picked it, we only have 25 for the second. Once we pick the second, we only have 24 for the third, and so on for the fourth. This gives us instead a pretty generous choice of 26 × 25 × 24 × 23 passwords.
The answer to this problem is =<span><span><span><span>−9/</span>10</span>x</span>+<span><span>−85/</span><span>6</span></span></span>
Answer: x = 9/4, y = 7/6
║<span>2x + 3y = 8
</span>║<span>4x - 6y = 2
</span>║4x + 6y = 16
║4x - 6y = 2
Add both equations together:
8x = 18
x = 9/4
Sub x = 9/4 into 2x + 3y = 8
2(9/4) + 3y = 8
9/2 + 3y = 8
3y = 7/2
y = 7/6
Answer:
(a) Number of inches that have burned from the candle since it was lit is (1.1t) inches
(b) The remaining length of the candle is (16 - 1.1t) inches
Step-by-step explanation:
(a). Length of candle before it was lit = 16 inches
Constant rate at which at which candle burns = 1.1 inches per hour
Let t represent the number of hours that have elapsed since the candle was lit
In 1 hour, 1.1 inches of the candle burned
Therefore, in t hours, (1.1t) inches of the candle would have burned since the candle was lit
(b) Remaining length of candle = length of candle before it was lit - length of candle that have burned = 16 inches - 1.1t inches = (16 - 1.1t) inches
<h3>
Answer: Bottom right corner (ie southeast corner)</h3>
This 3D solid is a strange sideways bowl shape. Each cross section is a ring to show the empty space.
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Explanation:
Check out the diagram below. The graph was created with GeoGebra. We have y = x^2 in red and x = y^2 in blue.
The gray region is the region between the two curves. We spin this gray region around the horizontal green line y = 1 to generate the answer mentioned above.
Note how (1,1) is a fixed point that does not move as this is on the line y = 1. Every other point moves to sweep through 3D space to create the solid figure. One way you can think of it is to think of propeller blades. Or you can think of a revolving door (the door is "flat" so to speak, but it sweeps out a 3D solid cylinder).
