Răspuns: a, b, c sunt invers proporționale cu 4, 5, 12 =>
=> a*4=b*5=c*12=k
a) a*4=b*5=c*12=k => a=k/4 }
b=k/5 } => c este cel mai mic => c=30
c=k/12 }
c=k/12 => k=c*12
k=30*12=360
a=k/4
a=360/4=90
b=k/5
b=360/5=72
b)a=k/4; b=k/5; c=k/12
a+b+c=64
k/4+k/5+k/12=64
15k/60+12k/60+5k/60=64
32k/60=64
k=(60*64)/32=120
a=k/4=120/4=30
b=k/5=120/5=24
c=k/12=120/12=10
c)a*4=b*5=c*12=k => a=k/4 }
b=k/5 } => a este cel mai mare => a=60
c=k/12 }
a=k/4 => k=a*4
k=60*4=240
b=k/5=240/5=48
c=k/12=240/12=20
d)a*4=b*5=c*12=k => a=k/4 }
b=k/5 } => a este cel mai mare si c cel mai mic =>
c=k/12 }
=> a+c=1,2
a=k/4
c=k/12
k/4+k/12=1,2
3k/12+k/12=1,2
4k/12=1,2
k=(12*1,2)/4
k=3*1,2
k=3,6
a=k/4=3,6/4=0,9
b=k/5=3,6/5=0,72
c=k/12=3,6/12=0.3
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