Question

Determinati numarul natural n din urmatoarele proportii:
0,3n-1 supra 6= 1,(6) supra 5
8 supra 0,2n-3= 2 supra 0,25
0,(3) supra 2 = 0,5n-1 supra 9

Answer 1

0,3n-1/6= 1,(6)/5
1,(6)=(16-1)/9=15/9=5/3
3n/10-1/6=5/3 × 1/5
3n/10=1/3+1/6
3n/10=3/6
3n/10=1/2
n=10/6=5/3

8n/0,2-3= 2/0,25
40n-3=8
40n=11
n=11/40

0,(3)/2 = 0,5n-1/9
(1/3)/2 +1/9= n/2
(3+2)/18= n/2
5/18=n/2
n=10/18=5/9