Math

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Ms.lynch has 21 coins in nickles and dimes.Their total value is \$1.65. How many of each coin does she have?

21 - ( 0.05x + 0.10x)=1.50
21- 0.15x = 1.50
0.15x=21-1.50
0.15x=19.5
------
0.15 = 19.5/ 0.15
x=130 ??????

• Math -

Your equation makes no sense to me at all
An equation only is useful and meaningful if the variable has been defined.

Let the number of nickels be x
then the number of dimes is 21-x

Now for the value of those coins:
5x + 10(21-x) = 165
5x + 210 - 10x = 165
-5x = -45
x = 9
then 21-x = 12

So we have 9 nickels and 12 dimes.

check:
do I have a total of 21 coins ? YES
value of my coins
= 5(9) + 10(12) = 165
All is good!

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