You have at least $30 in change in your drawer,
consisting of dimes and quarters. Write an 
inequality that shows the different numbers of 
coins in your drawer.

Let D = the number of dimes.
1 dime is worth $.10, so
D dimes are worth $.10D

Let Q = the number of qyuraters.
1 quarter is worth $.25, so
Q dimes are worth $.25D

The worth of the Dimes + The worth of the 
quarters is at least $30

$.10D + $.25Q is at least $30, 
which means it is either $30 or more than $30

.10D + .25Q > 30

Your teacher may accept this answer. If not,
get rid of decimals:

  10D + 25Q > 3000

Then you can divide through by 5

   2D + 5Q > 600

The smallest number of coins you can have is
when there are 5 dimes and 118 quarters, or
123 coins, and there is no largest number of
coins.

Edwin