Pupils

There are 32 pupils in the classroom, and girls are two-thirds more than boys. a) How many percents are more girls than boys? Round the result to a whole percentage. b) How many boys are in the class? c) Find the ratio of boys and girls in the class. Write in the simplest form.

Correct answer:

c =  12
d =  20
p =  67 %
f =  3:5

Step-by-step explanation:

c+d=32
d = c+ 2/3c

c+d=32
d = c+ 2/3·c

c+d = 32
5c-3d = 0

Pivot: Row 1 ↔ Row 2
5c-3d = 0
c+d = 32

Row 2 - 1/5 · Row 1 → Row 2
5c-3d = 0
1.6d = 32


d = 32/1.6 = 20
c = 0+3d/5 = 0+3 · 20/5 = 12

c = 12
d = 20

Our linear equations calculator calculates it.

$p=100\cdot \frac{d-c}{c}=100\cdot \frac{20-12}{12}=\frac{200}{3}\%=67\%$

$f=\frac{c}{d}=\frac{12}{20}=\frac{3}{5}=0.6=3:5$

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