Bài 1: Yêu cầu số liệu: ●Xây dựng bảng số liệu theo phương pháp phân tổ có khoảng các đều nhau.
●Tổng số đơn vị của tổng thể:100 đơn vị; Số tổ: 4
Yêu cầu: Xác đinh khoảng cách tổ, số trung bình, trung vị, mốt?

i think it is everything has to equal 180 so, if i correct 4=c. 6=d. 8=a. 7=b. and the last question would be c. because they are parallel lines and they are congruent.

step-by-step explanation:

the reason everything has to equal to 180 is because that is how it works. i'm guessing that is its rule. 4 and 8 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 6 and 7 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 60+60 is 180. so, now you have your answer

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9

hope this !

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