Question

Barney and Betty break into a parking meter with $3.90 in dimes and quarters in it (legal disclaimer: don't do this) and agree that Barney will get all the dimes, and Betty will get all the quarters. (Barley isn't terribly bright) Barney ends up with four more coins than Betty. How much money did each get(

Answer 1

Barney got 14 dimes and Betty got 10 quarters.

Explanation:

Since there are only dimes and quarters in the parking meter, the total money must be equal to:

`0.1*dimes + 0.25*quarters = 3.9`

Since Barney got all the dimes and he has four more coins than Betty, then the number of dimes is:

`dimes = quarters + 4`

Applying the second expression on the first, we have:

`0.1*(quarters + 4) + 0.25*quarters = 3.9\\0.1*quarters + 0.4 + 0.25*quarters = 3.9\\0.35*quarters = 3.9 - 0.4\\0.35*quarters = 3.5\\quarters = (3.5)/(0.35) = 10`

`dimes = quarters + 4 = 10 + 4 = 14`

Barney got 14 dimes and Betty got 10 quarters.