Answer:
in my opinion anush has the better performance
Answer:
x^-13
Step-by-step explanation:
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Answer:
- 100 mL of 75% solution
- 150 mL of pure alcohol
Step-by-step explanation:
Let x represent the quantity (in mL) of pure alcohol needed for the mix. Then the amount of 75% needed is (250-x). The amount of alcohol in the mixture is ...
1.00x +0.75(250 -x) = 0.90(250)
0.25x +187.5 = 225 . . simplify
0.25x = 37.5 . . . . . . . . subtract 187.5
x = 150 . . . . . . . . . . . . . divide by 0.25
(250 -x) = 100 . . . . mL of 75% solution
You need 100 mL of the 75% solution and 150 mL of pure alcohol to obtain the desired mixture.
The second yes is the answer
A)
First note that the plates can have between 4 and 6 symbols so we will need to find the number of plates with 4 symbols, 5 symbols and 6 symbols. We add these to get the total. In this part repetition of symbols is allowed. Since there are 26 + 10 =36 possible symbols we look at each position on the plate and think of how many choices there are. We multiply the number f choices using the counting principal since the choices are each independent -- one symbol does not affect another. There are 36 choices for the first symbol, 35 for the second and so on. The number of plates is:
4-symbols = (36)(36)(36)(36)=36^4
5 symbols = (36)^5
6 symbols = 36^6
So the total here is: 36^4+36^5+36^6
B) Here we do not repeat symbols so there are 36 choices for the first symbol but only 35 for the next and 34 for the one after and so on.
4-symbols = (36)(35)(34)(33)
5 symbols = (36)(35)(34)(33)(32)
6 symbols = (36)(35)(34)(33)(32)(31)
So the total here is: (36)(35)(34)(33)+(36)(35)(34)(33)(32)+(36)(35)(34)(33)(32)(31)
c)
In order for there to be a repeated symbol we have 36 choices for the first symbol, 36 for the next and so on. However, for the last symbol we have to pick from one of the ones already selected so there are 3, 4 or 5 choices respectively.
4-symbols = (36)(36)(36)(3)
5 symbols = (36)(36)(36)(36)(4)
6 symbols = (36)(36)(36)(36)(36)(5)
So the total here is: (36^3)(3)+(36^4)(4)+(36^5)(5)
D)
The probability is given by (the number of plates with at least one repeated symbol)/(the total number of plates if repetitions are allowed) = (the answer to c) / (the answer to a)
