Question 183444: Sally has 7 times as many dimes as nickels. Their value is $3.00. How many nickels does she have? Answer by lizard(7) (Show Source):
You can put this solution on YOUR website! nickles-5--n--5n
dimes---10-7n-10(7n)
---------------300
5n+10(7n)=300
5n+70n=300
75n=300
/75_/75
n=4
nickles=4
dimes=7*4=28
a nickle is worth 5 cents and a dime 10. since we don't know how many nickles there are we'll use the variable n. there are 7 times as many dimes as nickles so thats 7n. you take the amount a coin is worth and then multiply it by it's value. it equals $3.00, but we'll use 300 cents. next we'll add them together so we get 5n+10(7n)=300 we start solving it and end up with 75n=300 divide by 75 and get n=4 that is how many nickles you have but you need to know how many dimes you have so 7*4=28 dimes
to check this use the following
28(10)+4(5)=300
280+20=300
300=300
this is a true answer
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