Question

Aflati un numar stiind ca daca adunam o treime din el cu o cincime din el obtinem 11.

Answer 1

x/3 + x/5 = 11
x ( 1/3 + 1/5) = 11
x ( 3 + 5 ) = 11 × 15 = 165
8x = 165
x = 165: 8 = 20,625

Answer 2

a/3+a/5=11
(5*a/15)+(3*a/15)=11*15/15 (Scapam de numitorul comun=15)
5*a+3*a=165
8*a=165
a=20,625