The answer to 1 plus 2 plus 3 plus 4 plus 0.78 plus 79 plus 80 is 169.78. This can be calculated by adding all the numbers together: 1 + 2 + 3 + 4 + 0.78 + 79 + 80 = 169.78.
Sum = 79*(79+1)/2 = 79*80/2 = 3160
There are infinitely many. Involving integers (whole numbers) there are: 0 + 80, 1 + 79, 2 + 78, .... 78 + 2, 79 + 1, 80 + 0, 81 + -1, 82 + -2, ..... When you include non-integers there are: ½ + 79½, 1½ + 78½, ... 1.1 + 78.9, 1.2 + 78.8, .... 3.1 + 76.9, 3.14 + 76.86, 3.141 + 76.859, 3.1415 + 76.8585, 3.14159 + 76.85841, ...., π + (80 - π)
The formula would be: X(X+1)=6162. X^2+X = 6162. X^2+X-6162 = 0; Factor this. (X+79)(X-78)=0. X+79=0 or X=-79; impossible. X-78=0; X=78; first page. Second page X+1=79. Therefore page numbers are 78 & 79. Check: 78*79=6162.
-1
There are an infinite number of sets with mean 80. Here are some: {80, 80, 80}, {80, 80, 80, 80, 80, 80} {79, 80, 81}, {79, 79, 80, 81, 81}, {79, 79, 80, 82} (1, 80, 159}, {-40, 200} To produce a set of n numbers with mean 80, start with any set of n-1 numbers. Suppose their sum is S. Then add the number 80*n-S to the set. You will now have n numbers whose sum is S+80*n-S = 80*n So the mean of this set is 80.
78 + 1 = 79
80
Sum = 79*(79+1)/2 = 79*80/2 = 3160
10x - 78 = 1, 10x = 79, x = 7.9
There are infinitely many. Involving integers (whole numbers) there are: 0 + 80, 1 + 79, 2 + 78, .... 78 + 2, 79 + 1, 80 + 0, 81 + -1, 82 + -2, ..... When you include non-integers there are: ½ + 79½, 1½ + 78½, ... 1.1 + 78.9, 1.2 + 78.8, .... 3.1 + 76.9, 3.14 + 76.86, 3.141 + 76.859, 3.1415 + 76.8585, 3.14159 + 76.85841, ...., π + (80 - π)
80
79
40 x 2 = 80 39 x 2 = 78 39 times with 1 remaining
1
mn = 80 m -n = -79 Substitute m - 80/m = -79 m^2 - 80 = -79m m^2 + 79m = 80 (NB Notice change of signs) Quadratic Eq'n m = { - 79 +/- sqrt[)79)^2 - 4(1)(-80)}] / 2(1) m = { - 79 +/- sqrt[6241 + 320}]/ 2 m = { -79 +/- sqrt[6561]} / 2 m = { - 79 +/- 81}/2 m = -160 / 2 = -80 or m = 2/2 = 1 Hence n = 1 + 79 = 80
The Anwser Is 80.
The formula would be: X(X+1)=6162. X^2+X = 6162. X^2+X-6162 = 0; Factor this. (X+79)(X-78)=0. X+79=0 or X=-79; impossible. X-78=0; X=78; first page. Second page X+1=79. Therefore page numbers are 78 & 79. Check: 78*79=6162.