Answer:
The even numbers between 0 and X represents an arithmetic sequence with a common difference of 2
The rule of arithmetic sequence = a + d(n - 1)
Where a is the first term and n is the number of terms
So, for the even numbers between 0 and X
The first term = a = 0
d = 2
So, we need to find n at the last term which is X
∴ X = 0 + 2 ( n -1 )
∴ n - 1 = X/2
∴ n = X/2 + 1
The sum of the arithmetic sequence = (n/2) × (2a + (n−1)d)
Substitute with a and d and X
So, the sum = (n/2) * (2*0 + (n−1)*2)
= (n/2) * ((n−1)*2)
= n(n-1)
= (X/2 + 1) * (X/2)
= X/2 by (X/2 + 1)
So, The quick way to add all even numbers between 0 and X always works.
Retail price
1.34×35=46.9
Retail price
1.34×56=75.04
Answer:
9(8+y)
Step-by-step explanation:
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Using Gauss's method
Total number of terms = [15-(-129)]/4+1=36+1=37
Add
S=15+11+7+....-125-129
S=-129-125-...+7+11+15
--------------------------------
2S=-114-114-114...(37 times)
=>
sum=S=(1/2)*(-114)*37=-2109
Using AP, T(n)=15+11+7+....-129
T(n)=19-4n => T(1)=15, T(37)=-129
S(n)=(1/2)(37)(T(1)+T(37)=(1/2)37(15-129)=2109
A) The total number is the sum of all the frequencies
2+5+8+12+11+6=44
Answer: 44
B) The width is (upper limit - lower limit) / 2
(35-21) / 2 = 7
(50-36) / 2 = 7
(65-51) / 2 = 7
(80-66) / 2 = 7
(95-81) / 2 = 7
(110-96) / 2 = 7
Answer: the width is 7
C) The midpoint is the lower limit + the width
36+7=43
Answer: the midpoint is 43
D)The modal is the class with more frequency
In this case 66-80 with 12
Answer: class 66-80
E) We use the width formula
lower limit = 111
width = 7
upper = (width * 2) - lower
upper = (7 * 2) + 111
upper = 125
Answer: class 111-125