Class pupil calculation

In the first and second years, there are 58 pupils in a pile. In the first and third years, there are 57 pupils. In the second and third years, there are 59 pupils. How many students are there:
a) In all of them, to the dromedary,
b) In individual classes?

Final Answer:

a =  28
b =  30
c =  29
x =  87

Step-by-step explanation:

a+b=58
a+c=57
b+c=59

a+b = 58
a+c = 57
b+c = 59

Row 2 - Row 1 → Row 2
a+b = 58
-b+c = -1
b+c = 59

Row 3 + Row 2 → Row 3
a+b = 58
-b+c = -1
2c = 58


c = 58/2 = 29
b = -1-c/-1 = -1-29/-1 = 30
a = 58-b = 58-30 = 28

a = 28
b = 30
c = 29

Our linear equations calculator calculates it.

$x=a+b+c=28+30+29=87$

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