Question

aflati trei numere rationale ce sunt invers proportionale cu 0,{3} ; 0,25 ; 0,2 si au media artimetica egala cu 60

Answer 1

fie a, y si z numerele cautate

a x 0,(3)= y x 0,25= z x 0,2
a x 3/9= y x 25/100= z x 2/10 = k
a x 3/9= k 
a x 1/3= k
a= k : 1/3
a= k x 3/1
a=3k
y x 25/100=k
y x 5/20=k
y x 1/4=k
y=k : 1/4
y=k x 4/1
y=4k
z x 2/10=k
z x 1/5=k
z=k : 1/5
z= k x 5/1
z= 5k
(a+y+z):3=60
a+y+z=60 x 3
a+y+z= 180
3k+4k+5k=180
12k=180
k=15
a=45
y=60
z=75