Let the youngest sister be n years
Lana will be 2n years, as her youngest sister is half her age
The age of the twins separately will be 2n-2 as they are 2 years younger than Lana
So, the equation looks like this:
n + 2n + 2(2n-2) = 45
Now solve for n:
3n + 4n - 4 = 45
7n - 4 = 45
7n = 49
n = 7
So the youngest sister is 7, Lana is 14 and the twins are 12. 14 + 12 + 12 + 7 =45
1.) y=3
2.) y=13
2y + y = 3y , 22+17= 39
3y = 39 , divide 3 on each side (which cancels out the 3 with the y which leaves you with y)
3.) y=10
3y - y = 2y , 35-15= 20
2y=20 , do the same as # 2.
4.) y=4
9y - 5y = 4y , 48-32= 16
4y=16, do the same as #2 & #3
5.) (4,5)
x + 3y = 19
2x - 3y = -7
solve for x first ; x + 2x= 3x , 19-7 = 12; 3x = 12 ; divide 3 ; x= 4. You know have to make the x's cancel out. so I will multiply -2 on the first equation. -2(x+3y=19)
-2x - 6y = -38
2x - 3y = -7
Now solve for y ; -6y + -3y = -9y , -38 + -7 = -45; -9y=-45 ; divide by -9 (since they are both negative your answer will be positive) ; y= 5
6.) (6,8)
x + 4y = 38
-x - 3y = -30
solve for y first ; 4y - 3y = y , 38-30 = 8; y=8 (that simple!) Now you need to find a common multiple for 4 & 3 which is 12. So you will have to multiply each equation by either 4 or 3.
(x + 4y = 38)*3 = 3x + 12y = 114
(-x - 3y = -30)*4 = -4x - 12y = -120
solve for x ; 3x - 4x = -x , 114-120= -6 ; -x=-6. Since the x has a negative that means there's still a 1 there so -1x=-6 ; you will need to divide this which makes the 6 a positive; x=6
Answer:
It will take Ellie 64 minutes to put as many boxes as possible.
Step-by-step explanation:
Let us work with meters.
The dimensions of Ellie's boxes in meters are: 0.45m by 0.40m by 0.35 ( <em>to convert from centimeters to meters we just divide by 100, because 1m =100cm).</em> therefore the volume of each box is:
<em>
</em>
Now the dimensions of the empty van are 3.6m by 1.6m by 2.1 m, therefore its volume 
is:
So the amount of boxes that Ellie can put in the van is equal to the volume of the van divided by the volume 
of each box:
So 192 boxes can be put into the van.
Now Ellie can put 3 boxes in the van in 1 minute, therefore the amount of time it will take her to put 192 boxes into the van will be:
So it takes Ellie 64 minutes to put as many boxes into the van as she can.
265/5 = 53/1
53 miles per hour.
*I hope this helped!
D 7
A million apologies if I’m wrong half of my brain is still on vacation!
