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va rog mult, dau coroana


Va Rog Mult Dau Coroana class=

Răspuns :

notam p=nr de probleme care trebuie să fie rezolvate

I zi⇒ 20%dinp=20p/100=p/5

aflăm restul  p-p/5= (5p-p)/5= 4p/5

II zi⇒ 25%din rest= 25/100*4p/5=

=100p/500=100p/500=p/5

III zi⇒ 96 probleme

I zi+II zi+III zi= p, toate problemele

p/5+ p/5+ 96= p

p/5 + 480/5=5p/5  am adus la numitor comun 5

480= 5p-2p

p=480:3= 160

I zi⇒ p/5=160/5=32

II zi⇒p/5=160/5=32

total 160 probleme, prima zi 32, a doua zi 32, a treia zi 96

Răspuns:

[tex]20/100*x=x/5-prima.saptamana\\\\x-x/5=5x/5-x/5=4x/5-rest\\\\25/100*4x/5=x/5-a2a.saptamana\\\\x/5+x/5+96=x\\\\numitor.comun-5\\\\x+x+480=5x\\\\480=5x-2x\\\\x=480:3\\\\x=160-prob.in.total\\\\\\160:5=32-rezolvate.prima.sapt\\\\160-32=128-rest\\\\25/100*128=32-rezolvate.a2a.sapt[/tex]