. How many dimes does he have?

Question

John has $1.85 in nickels and dimes. Dimes are 1more than twice the number of nickels. How many dimes does he have?

Answer 1

If you take out the one dime extra, you're looking for a combination that makes $1.75. I made a chart then used guess and check to narrow it down. I had to remember that the number of dimes was twice the number of nickels [plus the dime I took out]:

 

dimes    nickels   total $

  2n          n

  10          5        1.25   too small

  12          6        1.50

  14          7        1.75

 

You have 15 dimes and 7 nickels.