Question

Exercitiul 3 ca nu mai stiu

Answer 1

$a + b = 210$

$a - \frac{a}{6} = 2(b + \frac{a}{6})$

$\frac{5a}{6} = 2b + \frac{2a}{6}$

$\frac{5a}{6} - \frac{2a}{6} = 2b$

$\frac{3a}{6} = 2b$

$= > \frac{a}{2} = 2b = > a = 4b$

$b = 210 - a$

$a = 4(210 - a)$

$a = 840 - 4a$

$5a = 840 = > a = 840 : 5 = > a = 168 \: lei \: are \: Andrei$

$b = 210 - 168 = > b = 42 \: lei \: are \: Bogdan$

Answer 2

Răspuns

Explicație pas cu pas:

Notez ,, a "  suma  lui Andrei   si  ,, b " = suma lui Bogdan

a + b = 210

a - a / 6 = 2 × ( b + a / 6 )

( 6 a - a ) / 6 = 2 × b + 2 a / 6

5 a / 6 - 2 a / 6 = 2 × b

3 a / 6 = 2 × b

⇒  a / 2 = 2 × b  ⇒  a = 4 × b

_______________________________________________________

a + b = 210

4 × b + b = 210

5 × b = 210  

b = 210 : 5     ⇒  b = 42 lei are Bogdan

a = 210 - 42   ⇒  a = 168 lei are Andrei

_____________________________

Verific:  

168 - 168 : 6 = 2 × ( 42 + 168 : 2)

168 - 28 =  2 × ( 42 + 28 )

140 = 2 × 70 ( corect)