Students 5637

There are 21 students in the class, two times more boys than girls. How many boys and how many girls are in the class?

Correct answer:

c =  14
d =  7

Step-by-step explanation:


c+d = 21
c = 2d

c+d = 21
c = 2·d

c+d = 21
c-2d = 0

Row 2 - Row 1 → Row 2
c+d = 21
-3d = -21


d = -21/-3 = 7
c = 21-d = 21-7 = 14

c = 14
d = 7

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