Question

24. Determinati a,b,c din sirul de rapoarte egale a/3=b/5=c/7 stiind ca a+b+c=60​

Answer 1

Răspuns:

a=3K

b=5K

c=7K

3k+5k+7k=60

15k=60

k=60÷15

k=4

a=3×4=12

b=5×4=20

c=7×4=28

Answer 2

$\huge \frac{a}{3} = \frac{b}{5} = \frac{c}{7} = k$

$\\ \\ \\ \huge \frac{a}{3} = k \rightarrow \: a = 3k \\ \\ \\ \\ \huge \frac{b}{5} = k \rightarrow \: b= 5k \\ \\ \\ \\ \huge \frac{c}{7} = k \rightarrow \: c = 7k$

$\\ \\ \\ \\ \huge \: a + b + c = 60 \\ \\ \huge \: 3k + 5k + 7k = 60 \\ \\ \huge \: 15k = 60 \\ \\ \huge \: k = 60 \div 15 \\ \\ \huge \underline{k = 4}$

$\\ \\ \\ \\ \\ \\ \huge \: a = 3k \\ \huge k = 4 \rightarrow \: a = 3 \times 4 \rightarrow \: \\ \\ \huge \rightarrow\pink{\boxed{ a= 12}}$

$\\ \\ \\ \huge \: b = 5k \\ \huge k = 4 \rightarrow \: b = 5\times 4 \rightarrow \: \\ \\ \huge \rightarrow\pink{\boxed{ b= 20}}$

$\\ \\ \\ \huge \: c= 7k \\ \huge k = 4 \rightarrow \: c = 7 \times 4 \rightarrow \: \\\ \\ \huge \rightarrow\pink{\boxed{ c= 28}}$

PROBA:

$a + b + c =60 \\ 12 + 20 + 28 = 60 \\ 60 = 60 \blue{ \: \: \: \: \: \: \: \: Adevărat}$