x= number of dimes
x+6= number of quarters
5(x+6)= number of nickels
$5.40= 540 cents
Add the number of each coin and set it equal to the total in cents.
x + (x + 6) + 5(x + 6)= $5.40
multiply 5 by parentheses; change dollar total to cents
x + (x + 6) + (5 * x) + (5 * 6)= 540
x + (x + 6) + 5x + 30= 540
combine like terms
7x + 36= 540
subtract 36 from both sides
7x= 504
divide both sides by 7
x= 72 dimes
x + 6= 78 quarters
5(x + 6)= 390 nickels
CHECK
72 + 78 + 390= 540
540= 540
ANSWER: There are 72 dimes, 78 quarters and 390 nickels.
Hope this helps! :)