Divide 5 tons of coal into 9 parts, each weight is (). 90% x-215 = 80% + 215 (how to calculate the equation, step by step)

Divide 5 tons of coal into 9 parts, each weight is (). 90% x-215 = 80% + 215 (how to calculate the equation, step by step)

The 5 tons of coal are divided into 9 parts, each weight is 5 / 9 tons, each is 1 / 9 of this ton of coal. 90% x-215 = 80% + 2150.9x-215 = 0.8x + 2150.9x-0.8x = 215 + 2150.1x = 4300 x = 4300

100 people participated in the quick calculation test, a total of 10 questions. The number of correct answers to each question is shown in the table below: question number 1 23 4 5 6 7 8 9 10, number of correct answers 93 90 86 9
A total of 100 people took part in the quick calculation test, with 10 questions in total. The number of people who answered each question correctly is shown in the table below: question number 1 23 4 5 6 7 8 9 10
The number of correct answers is 93 90 86 91 80 83 72 75 78 59. It is stipulated that if 6 or more questions are correctly answered, it is a pass. According to the above table, how many people are there at least

There were 7.10.14.9.20.17.28.25.22.41 people who made mistakes from 1 to 10 respectively. There were 193 mistakes in 7 + 10 + 14 + 9 + 20 + 17 + 28 + 25 + 22 + 41
193 / 4 = 48.25100, at most 49 people failed, at least 100-49 = 51 people passed
Pass rate 51%

How to solve this problem: 4,9,20,43, () a.80 b.62 c.90 d.111

The previous number x2 + (ordinal - 1) = the next number
43x2+4=90
Choose D
4X2+1=9
9X2+2=20
20X2+3=43
43X2+4=90