Hello!
The words at least means that the worker needs to work 8, 9 or 10 hours. We can add probabilities, so we will add .6 (for those working 8 hours), .15 (for those working 9 hours) and .08 (for those working 10 hours) to get a total probability of .83.
Hope this helps!
Answer:
Yes (432 = 9 x48).
Step-by-step explanation:
The trick you need to know is the theorem that says that if the digits in a number add up to a multiple of 9, then the number itself is divisible by 9.
So we go 4+3+2 = 9.
So as this sum of 9 is divisible by 9, it means 432 is also divisible by 9.
If you want to work out the actual answer of 432 divided by 9, you can estimate it by doing 450 ÷ 9 = 50. Then see that 432 is 18 less than 450. And 18 = 2x9. So the answer to the division is 50-2 = 48.
(√10)/(√3)*(√3)/(<span>√3); multiplied by the conjugate which is = (</span><span>√30/3)</span>
<h3>
Answer: 28</h3>
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Explanation:
Method 1
Imagine a table with 8 rows and 8 columns to represent all possible match-ups. You can actually draw out this table or just think of it as a thought experiment.
There are 8*8 = 64 entries in the table. Along the northwest diagonal, we have each team pair up with itself. This is of course silly and impossible. We cross off this entire diagonal so we drop to 64-8 = 56 entries.
Then notice that the lower left corner is a mirror copy of the upper right corner. A match-up like AB is the same as BA. So we must divide by 2 to get 56/2 = 28 different matches.
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Method 2
There are 8 selections for the first slot, and 8-1 = 7 selections for the second slot. We have 8*7 = 56 permutations and 56/2 = 28 combinations.
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Method 3
Use the nCr combination formula with n = 8 and r = 2
There are 28 combinations possible. Order doesn't matter (eg: match-up AB is the same as match-up BA).
Notice how the (8*7)/2 expression is part of the steps shown above in the nCr formula.
You can simply collect terms, subtract the constant and divide by the x-coefficient. It is generally considered easier to do those steps if you eliminate fractions first (multiply by 12).
Multiply by 12
... 4(x -1) +3(x +5) = 6
... 4x -4 +3x +15 = 6 . . . . . eliminate parentheses
... 7x +11 = 6 . . . . . . . . . . . .collect terms
... 7x = -5 . . . . . . . . . . . . . . subtract the constant 11
... x = -5/7 . . . . . . . . . . . . . divide by the x-coefficient
_ _ _ _ _ _ _
Here it is the other way.
... x(1/3 +1/4) +(-1/3 +5/4) = 1/2
... (7/12)x + 11/12 = 1/2 . . add the fractions to finish collecting terms
... x + 11/7 = 6/7 . . . . . . . multiply by 12/7
... x = -5/7 . . . . . . . . . . . subtract 11/7
At the third step here, you could subtract 11/12 before doing the multiply. You get the same answer, but you have to do the extra conversion of 1/2=6/12.
