Răspuns :
a + b +c = 990
a : b = 4
b : c = 2
a = 4b = 4 * 2c = 8c
b = 2c
8c + 2c +c = 11c =990
c = 990 :11
c = 90
b = 2 *90 = 180
a = 8 * 90= 720
a : b = 4
b : c = 2
a = 4b = 4 * 2c = 8c
b = 2c
8c + 2c +c = 11c =990
c = 990 :11
c = 90
b = 2 *90 = 180
a = 8 * 90= 720
a,b,c cele trei numere
a+b+c=990
a:b=4 b=a:4
b:c=2 (a:4):c=2 a/4:c=2 c=a/4:2 =a/4*1/2=a/8
inlocuim tot ce stim in suma de mai sus
a+a/4+a/8=990 aducem la acelasi numitor comun 8 amplificand cu 8 si 2
(8a+2a+a)/8=990
11a/8=990 a=990*8:11=720
b=720:4=180
c=720:8=90
proba: 720+180+90=990
a+b+c=990
a:b=4 b=a:4
b:c=2 (a:4):c=2 a/4:c=2 c=a/4:2 =a/4*1/2=a/8
inlocuim tot ce stim in suma de mai sus
a+a/4+a/8=990 aducem la acelasi numitor comun 8 amplificand cu 8 si 2
(8a+2a+a)/8=990
11a/8=990 a=990*8:11=720
b=720:4=180
c=720:8=90
proba: 720+180+90=990