Question

At lectures in four classrooms there are 870 students, and in the first audience there are 60 students more than in the second, in the second - 20 students less than in the third, and in the third - 50 less than in the fourth. How many students in each class Audience?

Answer 1

Let the fourth audience of students, then

X + (x-50) + (x-50-20) + (x-50-20 + 60) = 870
X + x-50 + x-70 + x-10 = 870
4x-130 = 870
4x = 870 + 130
Х = 1000/4
Х = 250 people in the fourth
250-50 = 200 people in the third
200-20 = 180 people in the second
180 + 60 = 240 people in the first

Answer 2

let in second audience number of students = x
in first audiences = x +60
in 3rd audience = x +20
in fourth audience = x + 70

total number of students= 870
x + x +60 + x +20 + x +70 = 870
4x + 150 = 870
4x = 720
x = 180

now ,
in 1st audience = 180 +60 = 240
2nd audience = 180
3rd audience = 180+20 = 200
4th audience = 180+70= 250