Answer: 259/260 or 0.99615 (depending on which answer format your teacher wants)
There are 10 numbers in the set {0, 1, 2, ..., 9}. There are 26 letters in the set {A, B, C, ..., Z}. Multiply those values: 10*26 = 260. So there are 260 ways to pick a number followed by a letter. One example is 7P.
There is only one way Matthew can get the correct answer, and there are 260 - 1 = 259 ways to get the wrong answer. We divide 259 over 260 to get the probability of getting the incorrect answer, which is 259/260.
If you need this fraction in decimal form, then use a calculator to find that 259/260 = 0.99615 approximately
Let X = the 29% alloy and Y = the 60% alloy.
They want a total of 80kg, so you have X +Y = 80
Rewrite that to get X = 80-Y
You also want 0.20X + 0.60Y = 0.52(80)
Replace X with 80-y:
0.20(80-y) + 0.60y = 0.52(80)
Simplify:
16 - 0.20y + 0.60y = 41.6
Combine like terms:
16 +0.40y = 41.6
Subtract 16 from each side:
0.40y = 25.6
Divide both sides by 0.40
y = 25.6 / 0.40
y = 64
Now you have Y replace y with 80 in X = 80-Y
X = 80 - 64
X = 16
They need 64 Kg of the 60% alloy and 16 Kg of the 20% alloy.
Answer:
-3
4 - 7 = -3.
-3 + 7 = 4.
They are in a fact family.
The answer is -3.
Hope it helps!
(a-b)^2 = a^2-2ab+b^2
(8-5i)^2 = 8^2-2(8)(5i)+(5i)^2
= 64-80i+25i^2
i^2=-1
So
= 64-80i+25(-1)
=64-25-80i
= <em><u>39 - 80i</u></em>
which is your answer :)
For each <em>x</em> in the interval 0 ≤ <em>x</em> ≤ 5, the shell at that point has
• radius = 5 - <em>x</em>, which is the distance from <em>x</em> to <em>x</em> = 5
• height = <em>x</em> ² + 2
• thickness = d<em>x</em>
and hence contributes a volume of 2<em>π</em> (5 - <em>x</em>) (<em>x</em> ² + 2) d<em>x</em>.
Taking infinitely many of these shells and summing their volumes (i.e. integrating) gives the volume of the region:
