Răspuns:
Explicație pas cu pas:
(a+6)+(b+6)+(c+6)+(d+6)=77
a+b+c+d+24=77
a+b+c+d=77-24
a+b+c+d=53 ani au acum impreuna
a=b:3 => b=3a
c=a:4-1 => a=4y => c=(4y:4)-1 => c=y-1
d=(a:2)x5 => d=(4y:2)x5 => d=2yx5 => d=10y
b=3x4y => b=12 y
a) |__|__|__|__|
b) |__|__|__|__|__|__|__|__|__|__|__|__|
c) |__|-1
d) |__|__|__|__|__|__|__|__|__|__|
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4y+12y+y-1+10y=53
27y-1=53
27y=53+1
27y=54
y=54:27
y=2
a=2x4=8 ani
b=2x12=24 ani
c=2-1=1 an
d=2x10=20 ani
8+24+1+20=54 ani