Question

suma a trei numere nenule a b c este 21. stiind ca numerele 20% din a 25% din b si 30%din c sunt direct proportionale cu numerele 1/2 35/48 si 1 aflați numerele a b si c

Answer 1

a+b+c=21
20% din a=20/100×a=1/5×a=a/5
25% din b=25/100×b=1/4×b=4/b
30% din c=30/100×c=3/10×c=3c/10
a/5;b/4;3c/10 dupa cu 1/2;35/48;1
a/5/1/2=b/4/35/48=3c/10/1=k
a/5××2/1=4/4×48/35=3c/10/1=k
2a/5=12b/35=3c/10=k
a=5k/2
b=35k/12
c=10k/3
5k/2+35k/12+10k/3=21 aducem la acelasi numitor
30k+35k+40k=252
105k=252
k=252/105
a=(5×252/105)/2=252/21/2=252/21×1/2=126/21=6
b=(35×252/105)/12=252/3/12=252/3×1/12=21/3=7
c=(10×252/105)/3=(2×252)/21/3=2×252/21×1/3=2×84/21=2×4=8