Answer: No, he is not correct
The number of combinations is 190
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Work Shown:
We have 10 shirts, 6 hats, and 4 scarves. This is 10+6+4 = 20 items total.
If we randomly pick out an item, then we have 20 to choose from. After selecting that first item, we have 20-1 = 19 items left to choose from.
So there are 20*19 = 380 different permutations. Order matters with permutations.
Since we aren't worried about order, this means that we've double counted so we have to divide by 2 to fix it.
So there are 380/2 = 190 combinations.
You can use the nCr combination formula with n = 20 and r = 2 to get the same result.
Volume equals 60 centimeters
Answer:
S = 1.25
B = 3.50
Step-by-step explanation:
I assume you need to know how much a burger and how much a soda is.
Basically it's a system of equations.
5B + 9S = 28.75
10B + 10S = 47.5
There are a few ways to do this, if you like I can show another, but this is how I usually solve a normal system of equations.
First solve for one variable in one equation. I am going to choose to solve for B in 10B + 10S = 47.5
10B + 10S = 47.5 (divide the whole thing by 10)
B + S = 4.75 (subtract S from both sides)
B = 4.75 - S
Now plug this B into the other equation.
5B + 9S = 28.75
5(4.75 - S) + 9S = 28.75
23.75 - 5S + 9S = 28.75 (Now just solve for S
4S = 5
S = 5/4
S = 1.25
Now plug THIS back into the first one.
B = 4.75 - S
B = 4.75 - 1.25
B = 3.50
Answer: r = -5/18
Step-by-step explanation: You solve -3(1+6r)+12=14
-3-18r+12=14 (When distributed)
-18r+9=14
-18r=5
r=-5/18