2/a = 5/b = 4/c si a + b + c = 99
2/a=5/b =>b=5a/2, 2/a=4/c =>c=4a/2 deci a+5a/2+4a/2=99 =>
2a/a+5a/2+4a/2=99 =>11a/2=99 => a/2=9 => a=18
2/a=5/b => a=2b/5, 5/b=4/c =>c=4b/5 deci 2b/5+b+4b/5=99 =>
2b/5+5b/5+4b/5=99 =>11b/5=99 => b/5=9 => b=45
2/a=4/c =>a=2c/4, 5/b=4/c => b=5c/4 deci 2c/4+5c/4+c=99 =>
2c/4+5c/4+4c/4=99 => 11c/4=99 => c/4=9 => c=36