Boys and girls

There are 28 girls in the hall. Boys make up 5/7 of all the children. How many children are there in total, and how many are boys?

Final Answer:

c =  70
s =  98

Step-by-step explanation:


c+28 = s
5/7 s = c

c+28 = s
5/7·s = c

c-s = -28
7c-5s = 0

Pivot: Row 1 ↔ Row 2
7c-5s = 0
c-s = -28

Row 2 - 1/7 · Row 1 → Row 2
7c-5s = 0
-0.29s = -28


s = -28/-0.28571429 = 98
c = 0+5s/7 = 0+5 · 98/7 = 70

c = 70
s = 98

Our linear equations calculator calculates it.



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