Question

Exercitiile 17 si 18. Va rog repede. Dau coroana

Answer 1

[tex]17. \text{Se noteaza cu x suma initiala.}\\ x-\dfrac{2}{5}\cdot x-19=8|\cdot 5\\ 5x-2x-95=40\\ 3x=135\\ \boxed{x=45\ lei}\\ \text{In prima zi a cheltuit:} \dfrac{2}{5}\cdot 45=\boxed{18\ lei}\\ \\ 18.\text{Se noteaza cu x pretul initial.}\\ x-\dfrac{5}{100}\cdot x-\dfrac{5}{100}\left(x-\dfrac{5}{100}\cdot x\right)=3610\\ x-\dfrac{x}{20}-\dfrac{1}{20}\left( x-\dfrac{x}{20}\right)=3610\\ \dfrac{19x}{20}-\dfrac{19x}{400}=3610|\cdot 400\\ \\ 380x-19x=1444000\\ 361x=1444000\Rightarrow \boxed{x=4000\ lei}[/tex]

Answer 2

prb.17:
ziua 1=a=2/3*s
ziua 2=b=19
s=2/3*s+19+8
3s=2s+57+24
s=81=)in prima zi cheltuie 2/3*81=54 lei