Awoman has 21 total coins in her pocket, all of which are either dimes or quarters. if the total value of her change is $3.90, how many dimes and how many quarters does she have? write the number of dimes, then the number of quarters separated by a comma.

Step-by-step explanation:

Givens

With this information we can construct a system of equations, where is dimes and is quarters.

, because there are 21 coins between dimes and quarters.

Now, we know that one dime values 10 cents, and one quarter values 25 cents.

, because the woman has $3.90 in total.

Then, we isolate in the first expression

And we substitute it in the second expression

Then, we use this value to find the other one

Therefore, the woman has 12 quarters and 9 dimes.

maximum area = xy = (16)(32) = 512 ft2

to maximize the area of the garden, the side of the fence parallel to the side of the house should be 32 ft long, and the other two sides should both have length 16 ft.'

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