Question

POR FAVOR ME AJUDEM !!!
A)50% DE 650
B)65% DE 450
C)25% DE 425
D)30% DE 325
E)80% DE 794

Answer 1

50% de 650
= 50/100 x 650
= 32500/100
= 325

65% de 450
= 65/100 x 450
= 29250/100
= 292,5

25% de 425
= 25/100 x 425
= 10625/100
= 106,25

30% de 325
= 9750/100
= 97,5

80% de 794
= 80/100 x 794
= 63520/100
= 635,2

Answer 2

Queremos achar y% de um valor x qualquer

x -------- 100%
k ------------ y%

(k representando y% de x)

Multiplicando em cruz, temos que

$100\%\cdot k=y\%\cdot x\\\\100\cdot k=y\cdot x\\\\\\\boxed{\boxed{k=\dfrac{y}{100}\cdot x}}$

Usaremos essa fórmula pra calcular as porcentagens
_____________________________________

a) 50% de 650

No caso, x = 650 e y = 50:

$k=\dfrac{y}{100}\cdot x=\dfrac{50}{100}\cdot 650=\dfrac{1}{2}\cdot650=325$

b) 65% de 450

x = 450, y = 65:

$k=\dfrac{65}{100}\cdot450=\dfrac{65\cdot45}{10}=\dfrac{2925}{10}=292,5$

c)

x = 425, y = 25:

$k=\dfrac{25}{100}\cdot425=\dfrac{1}{4}\cdot425=106,25$

d)

x = 325, y = 30:

$k=\dfrac{30}{100}\cdot325=\dfrac{3\cdot325}{10}=\dfrac{975}{10}=97,5$

e)

x = 794, y = 80:

$k=\dfrac{80}{100}\cdot794=0,8\cdot794=635,2$