Problema Solution

Joan has $3.50 in nickels, dimes, and quarters. She has the same number of nickels as quarters. She has twice as many nickels as dimes.

Write an equation that relates the number of each kind of coin to the amount of money that Joan has.

Answer provided by our tutors

set x,y,z be the number of nickles, dimes, quaters; respectively. 

We have: 

x = z

x = 2y

0.05x+0.1y+ 0.25z = 3.5

-> 0.1 y + 0.1 y +0.5y = 3.5

-> 0.7 y = 3.5 

-> y = 5

-> x= z = 2y = 10