at least how many dimes are there?

Question

a collection of quarters and dimes is worth more than $20. There are twice as many quarters as dimes,nat least how many dimes are there?

Answer 1

Let q = the number of quarters and d = the number of dimes

 

A collection of quarters and dimes is worth more than $20:

 

($0.25)*q + ($0.10)*d > $20

 

There are twice as many quarters as dimes:

 

q = 2d

 

Since q = 2d, let's substitute 2d in place of q in the first equation:

 

($0.25)*q + ($0.10)*d > $20

($0.25)*(2d) + ($0.10)*d > $20       [Substituted 2d for q]

0.50d + 0.10d > 20

0.6d > 20

 

d > 20/0.6

 

Solve for d.  Since d must be an integer, round decimal values up to the next integer.