Half, one fifth, one tenth, one seventeenth, one twenty sixth. What's the fifth number (2) one third, two fifths, three fifths, four sixths. What is the fifth and sixth?

Half, one fifth, one tenth, one seventeenth, one twenty sixth. What's the fifth number (2) one third, two fifths, three fifths, four sixths. What is the fifth and sixth?

(1) Fifth: one in 37;
Sixth: one in fifty
(2) The fifth: five out of ninety-nine;
Sixth: negative 6 / 143

What's the rule of 1-2-5-10-17-26
one
10,11,12,13,14,15,16
17,18,19,20,21,22,23,24,25
26,27,28,29,30,31,32,33,34,35,36，
Use the algebraic expression containing n to express the first number of the nth row, and the last is the total number of the nth row.
Find the sum of the number of the nth row

The first one is - 1
-1=-(0²+1)
-2=-(1²+1)
-5=-(2²+1)
-10=-(3²+1)
……
So the nth one is - [(n-1) ² + 1]

The law of 25 10 17 26
And then

5-2=3；
10-5=5；
17-10=7；
26-17=9；
……
See

There is a column of numbers 3, 7.11.15.19?

3+39*4=1599
（3+1599）*4/2=3204

One column number: 2,3,1,2,3,1,2,3,1.1, what is the 28th number?
One column number: 2,3,1,2,3,1,2,3,1.1, what is the 28th number? What is the sum of the 28th number?

Rule 2, 3, 1, repeat
28 divided by 3 = 9
So 28 is two
The sum of 28 numbers = (2 + 3 + 1) x9 + 2
=54+2
=56
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Given a + A + A + B + B = 19.5, a + A + B + B + B = 17.1, find the values of a and B

That is 3A + 2B = 19.5 (1)
2a+3b=17.1 (2)
Add
5a+5b=36.6
a+b=7.32
So 3A + 3B = 21.96 (3)
(3)-(2)
a=4.86
b=7.32-a=2.46

1/4,2/5,5/7,1,17/14,( ) A.25/17 B.26/17 C.25/19 D.26/19

1 / 10
The denominator is 4 5 7 10 14 (19)
The interval is 1 2 3 4 5
The molecule is 1 2 5 10 17 (26)
The interval is 1 3 5 7 9
So choose D

There are three numbers a, B and C. The average of a and B is 15, the average of B and C is 19, and the average of a and C is 17. What are the three numbers?
Using the method of primary school to solve the problem requires specific steps

The average of a and B is 15 = > A + B = 2 * 15 = 30
The average of B and C is 19 = > b + C = 2 * 19 = 38
The average of a and C is 17 = > A + C = 2 * 17 = 34
So a + B + C = (30 + 38 + 34) / 2 = 51
A=51-38=13.
B=51-34=17.
C=51-30=21.

There are three numbers a.b.c. the average of a and B is 15, the average of B and C is 19, and the average of a and C is 17

A＋B＝30
B＋C＝38
A＋C＝34
The last two equations add up to a + B + 2C = 72
By subtracting 2C from the first equation, 2C = 42
C＝21
Then a = 13 and B = 17

There are three numbers a β C, the average number of a β is 15, the average number of B β C is 19, and the average number of a β C is 17,

a+b=30
B+C=38
A+C=34
So a-c = - 8 = = = > A = 13 = = > C = 21 = = > b = 17