Question

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Answer 1

Răspuns:

Explicație pas cu pas:

1)

9m.................12 zile

18m...............x zile

x= (9*12)*18= 108/18=6 zile

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2)

(x,y,z) dp ( 2,5,7 )

x*y*z= 560

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x/2=y/5=z/7=k

x/2=k→x=2k

y/5=k→y=5k

z/7=k→z=7k

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x*y*z=560

2k*5k*7k= 560

70K³=560

K³=760:70

K³=8

K=2

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x= 2K=2*2=4

y=5k= 5*2=10

z=7k= 7*2=14

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3)

0,5=1/2

(0,3) = 3/9=1/3

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a/2=b/3=5c/2=k

a/2=k→a=2k

b/3=k→b=3k

c/2,5=k→c= 2,5k

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2K+3K+2,5K=36

7,5K=36

75K/10=¹⁰⁾36

75K=360

k= 360:75

K= 4,8

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a=2K=2*4,8= 9,6

b= 3k= 3*4.8=14,4

c= 2,5*4,8= 12

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4)

numere de doua cifre = 10,11,12 ....99   ...deci 90 de numere

numarul cazurilor favorabile =9 ...(10,20,30,40,50,60,70,80,90)

P= 9/90= 1*10 sau 10%