Question

Exercitiul d .va rogg

Answer 1

iei prima si ultima fractie x/21=5/7  => x=21*5/7  => x=15
apoi a doua fractie cu ultima  10/y=5/7  => y=7*10/5  => y=14
x+y = 15 + 14 = 29

Answer 2

   
Le voi rezolva pe toate:

[tex]\displaystyle\\ a)~125\%~\text{din}~32 =125\%\times32 = \frac{125}{100}\times 32 = \frac{5}{4}\times 32 =5\times 8=\boxed{\bf40}\\\\ b)~\frac{x+1}{6}= \frac{6}{9}\Longrightarrow x+1= \frac{6\times6}{9}= \frac{36}{9}=4 \Longrightarrow x = 4 - 1 = \boxed{\bf 3}\\\\ c)~p\%= \frac{30g}{120g + 30g}\times 100= \frac{30g~sare}{150g~solutie}\times 100= \frac{1}{5}\times 100=\boxed{\bf20\%} \\\\ [/tex]

[tex]\displaystyle\\ d)\\ \frac{x}{21} = \frac{5}{7} \Longrightarrow x= \frac{21\times5}{7} =3\times5=\boxed{\bf 15}\\\\ \frac{10}{y} = \frac{5}{7} \Longrightarrow y= \frac{10\times7}{5} =2\times7=\boxed{\bf 14}\\\\ x+y=15+14=\boxed{\bf29} [/tex]