One day, a, B and C do math problems. It is known that a has done 6 more than B, and C has done 2 times as much as a, 22 more than B, so they have done all of them______ A math problem

One day, a, B and C do math problems. It is known that a has done 6 more than B, and C has done 2 times as much as a, 22 more than B, so they have done all of them______ A math problem

Let B do X questions. From the meaning of the questions, we can get: (x + 6) × 2 = x + 22, & nbsp; & nbsp; & nbsp; 2x + 12 = x + 22, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 10; a: 10 + 6 = 16 (DAO); C: 16 × 2 = 32 (DAO); all: 10 + 16 + 32 = 58 (DAO); a: they have done 58 math questions. So the answer is: 58

Three students have done a total of 20 math problems, B is doing a problem is a 2 cup, a less than C do 5. Three students have done how many problems?

A
(20 + 1-5) / (1 + 2 + 1) = 4 questions
B
4 × 2-1 = 7 questions
C
4 + 5 = 9 questions
Analysis: sum multiple problem, draw line diagram

A big and small mathematical problem
Let f (x) = (n + 2) (n + 4) / ((n + 3) n)
How to find a

How do you do? Suppose the building owner is a senior high school student and has no limit knowledge. The simple method for junior high school students is as follows: the original formula can be changed to: ((n + 2) / N) * ((n + 4) / (n + 3)) to simplify: (1 + 2 / N) * (1 + 4 / (n + 3)). Note that no matter 2 / N or 4 / (n + 3) will gradually decrease with the increase of positive integer n