Math problem solving in algebra

Question

Janet has $2.05 in dimes and quarters. If she has four fewer  dimes than quarters how much money does she have in dimes.

Answer 1

If she has x quarters, then she has (x - 4) dimes

 

0.25x + .10(x - 4) = 2.05

 

25x + 10(x - 4) = 205

 

25x + 10x - 40 = 205

 

35x - 40 = 205

 

35x = 245

 

x = 7 quarters, so she has 7 - 4 = 3 dimes