Question

un joyero vende 13 anillos de oro y 18 de plata por 9405 euros. sabiendo que el anillo de oro cuesta el triple que el de plata ¿cual es el precio de cada anillo?

Answer 1

To solve this problem you must apply the proccedure shown below:

 1. You have that:

 - He sales 13 gold rings and 18 silver rings in 9405 euros.
 - The cost of the silver ring is three times the cost of the gold ring.

 2. Keeping the information above on mind, you have the following system of equations:

 x: the gold ring.
 y: the silver ring.

 x+y=9405
 x=3y

 3. Then, you have:

 (3y)+y=9405
 y=9405/4
 y=2351.23 euros

 x=3y
 x=3(2351.23)
 x=7053.75 euros

 The answer is: 
 - Gold ring=7053.75 euros
 - Silver ring=2351.23 euros