Question

Daca nr bc este eg cu 4% din nr abc,atunci calculati a+b+c.

Answer 1

abc:100*4=bc
4*abc=100bc
4*(100a+10b+c)=100*(10b+c)
400a+40b+4c=1000b+100c
400a-960b-96c=0
ca 96c sa se termine in 0 c=5
Deci:
400a-960b=480
Ca 960*b +480sa se termine in 00 b=7 sau b=2
b=2=> 400a-1920=480
400a=2400
a=6

b=7=> 400a-6720=480
400a= 7200
a=18 nu se poate!

deci a=6,b=2,c=5
proba 625:100*4=25 ok!

a+b+c=6+2+5=13