Answer:
Now: 6 yr mean age
in 10 yrs? 16 yr mean age
in 20 yrs? 26 yr mean age
Why? Because regardless of the relationship between each sibling's age, your always adding the 10yrs to each individual, which you are then dividing out to determine the mean age. See proof below:
Including anita, there are 6 people. We'll define each age as an unknown variable. Assume we know nothing about the relationships between their ages
for example sake
anita's age = a
sister 1's age = b
sister 2's age = c
brother 1's age = d
brother 2's age = e
brother 3's age = f
Now:
mean age = (a + b + c + d + e + f)/(6 people) = 6 yrs
in 10 yrs:
mean age = ((a+10) + (b+10) + (c+10) + (d+10) + (e+10) + (f+10))/(6 people)
mean age = (a + b + c + d + e + f + 60)/(6 people)
mean age = (a + b + c + d + e + f)/(6 people) + (60)/(6 people)
mean age = (a + b + c + d + e + f)/(6 people) + 10
Notice the first term is the same expression of the mean age for "Now"
Thus, in 10 yrs:
mean age = 6 + 10 = 16 yrs
The same principle applies for "x" yrs from now, as long as we know what the mean age is "Now"
Answer:
2x+y+2=0
Step-by-step explanation:
I from Mexico:)
The sum of the series 
is 44.
Step-by-step explanation:
The given series is 
To find the sum of the series, we need to substitute the values for k in the series.
![\sum_{k=1}^{4}\left(2 k^{2}-4\right)=\left[2(1)^{2}-4\right]+\left[2(2)^{2}-4\right]+\left[2(3)^{2}-4\right]+\left[2(4)^{2}-4\right]](https://tex.z-dn.net/?f=%5Csum_%7Bk%3D1%7D%5E%7B4%7D%5Cleft%282%20k%5E%7B2%7D-4%5Cright%29%3D%5Cleft%5B2%281%29%5E%7B2%7D-4%5Cright%5D%2B%5Cleft%5B2%282%29%5E%7B2%7D-4%5Cright%5D%2B%5Cleft%5B2%283%29%5E%7B2%7D-4%5Cright%5D%2B%5Cleft%5B2%284%29%5E%7B2%7D-4%5Cright%5D)
Now, simplifying the square terms, we get,
![[2(1)-4]+[2(4)-4]+[2(9)-4]+[2(16)-4]](https://tex.z-dn.net/?f=%5B2%281%29-4%5D%2B%5B2%284%29-4%5D%2B%5B2%289%29-4%5D%2B%5B2%2816%29-4%5D)
Multiplying the terms,
![[2-4]+[8-4]+[18-4]+[32-4]](https://tex.z-dn.net/?f=%5B2-4%5D%2B%5B8-4%5D%2B%5B18-4%5D%2B%5B32-4%5D)
Subtracting the values within the bracket term, we get,
Now, adding all the terms, we get the sum of the series,
Thus, the sum of the series is
Answer:
24 chairs in each class needed
25 classrooms
700 chairs total
how many extra chairs
chairs will be c
t is total
t= 25×c
opposite of multiplication is division( 25 is multiplying by c) c needs to be alone
25 classrooms times chairs equal total chairs
t is 700
700=25×c
700/25=25/25c
700/25=C
c is 28
so 28 chairs for 25 classrooms
they need 24 chairs per class
so there are 4 extra chairs per class
4×25 is 100
**or just multiply 25 classes and 24 chairs
25 times 24 is 600
there are 700 chairs
100 left over
so 100 extra chairs
Answer:
b
Step-by-step explanation:
4.75 rounds to 5 because the 7, 83 rounds to 80 because of the 3. 80*5=400
