Question

divida o numero 380 em tres parcelas que sejam inversamente porpocionais aos numeros 2,5 e 4. Quais são essas pacelas? me ajudem

Answer 1

x/2+x/5+x/4=380 < mmc= 20 

10x+4x+5x=7600
19x=7600
x=7600/19
x=400

400/2= 200

400/5= 80

400/4=100

As parcelas são  200  80 e 100 R$

Answer 2

$a+b+c=380\\\\2a\\\\4b\\\\5c\\\\a+b+c=\frac{1}{2}+\frac{1}{4}+\frac{1}{5}=\frac{10+5+4}{20}\\\\\frac{380}{\frac{19}{20}}=a\\\\380.\frac{20}{19}=2a\\\\400=2a\\\\a=\frac{400}{2}\\\\a=200\\\\400=4b\\b=\frac{400}{4}\\\\b=100\\\\400=5c\\\\c=\frac{400}{5}\\\\c=80$

Parcelas são = 200, 100 e 80