Gauss' method for addition relies on the fact that you can 'pair' certain numbers together. Look at the example:
1+2+3+4+5+6+7+8+9+10
We could manually add all these together from left to right but a clever way to think about this is if we add together the ends of the sum (10+1) we get 11. If we then move one in from the ends and add these (2+9) we also get 11. This means that 1+2+...+9+10 is the same as 11+11+...+11+11.
Because each 2 numbers adds to 11 we know the total number of 11's we have to add together is the length of the sum divided by 2. In our case 5 (10 ÷ 2). We need to add 5 lots of 11 to get our answer. This is the same as 11 × 5 which is easily seen to be 55.
(If you add the 10 numbers together on a calculator you'll see 1+2+3+4+5+6+7+8+9+10 = 55) so this method really makes it a lot quicker.
Looking at your sequence, if we pair the ends together we get 401 (400+1) and we multiply this by the length of the sequence divided by 2. In your case, 200 (400 ÷ 2).
So the sum of all the numbers from 1 to 400 must be 401 × 200 = 80,200.
Remember the steps:
1. Pair the ends together and add them
2. Times this number by the length of the sequence halved
Hope this helps.
Answer:
1. 1:4
2. y = 4 x X
3. yes
Step-by-step explanation:
1. every 1 minuet he cleans 4 shrimp
2. y is the number of shrimp and x is the time. if every miuet he cleans 4 shrimp, then that means you have to multiply the shrimp by the minuets. for example, if he spends 2 minuets, he cleans 8 shrimp because 2 x 4 = 8.
3. This is a proportional relationship because if you were to put this on a graph, it would be a strait line. for example, if you were to plot x (the time) on a line (this line would go horizontal) and y (shrimp) on the line (this line goes verticle) 1 minuet = 4 shrimp. 2 minuets = 8 shrimp. 3 minuets = 12 shrimp. 4 minuets = 16 shrimp.
i hope this helps. tell me if this is too confusing or if you need more help. have a great day :)
Use proportions here - 8/5.2 = 96/width of actual car. using cross multiplication, 5.2*96 = 8x. this gives you 499.2 = 8x. divide both sides by eight to get x=62.4. the width of the actual car is 62.4 inches.
Answer:
D
Step-by-step explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
To calculate m use the slope formula
m = ( y₂ - y₁ ) / (x₂ - x₁ )
with (x₁, y₁ ) = (3, 6) and (x₂, y₂ ) = (8, 4)
m = 
= - 
, hence
y = - x + c ← is the partial equation
To find c substitute either of the 2 points into the partial equation
Using (8, 4), then
4 = - 
+ c ⇒ c = 4 + = 
y = - x + ← equation of line
I'm assuming this is a system of equations you want solved so,
x = -y + 3
-2(-y+3)+4y = 6
2y - 6 + 4y = 6
6y = 12
y = 2
x + 2 = 3
x = -1
(-1,2)
