Question

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DAU Coroană

Answer 1

x/y=40/100=4/10=0.4, (3/40+100)/(40+100)=220/140=22/14=11/7,

regula de trei simpla

x................100%

y....................n%, n%=100y/x=100x100/40=250%, y reprezinta 250% din x

Answer 2

x = 40% din y ⇒ 40 / 100 = 2 / 5 din y ⇒ 2 y = 5 x ⇒ x = 2 y / 5

a) x / y = 2 / 5 ( 5 x = 2 y )

b) ( 3 x + y ) / ( x + y ) = ( 3 × 2 y / 5 + y ) : ( 2 y / 5 + y ) =

= ( 6 y / 5 + 5 y / 5 ) : ( 2 y / 5 + 5 y / 5 ) =

= 11 y / 5 × 5 / 7 y =

= 11 / 7

c)

100% .............x

a %...................y

____________

a % × x = y

a / 100 × 40 / 100 = y = > 100 × 100 / 40 = 250 ; y reprezinta 250% din x