Problema Solution
When Lucas dumped the coins out of his piggy bank, he noticed that there were only nickels and dimes, and the number of nickels was twice the number of dimes. If there were 50 nickels, what was the total value of the coins Lucas dumped out of his piggy bank?
Answer provided by our tutors
let
n = 50 nickles the number of nickels
d = the number of dimes, d>0, d is integer
the number of nickels was twice the number of dimes:
n = 2d
2d = n
2d = 50 divide both sides by 2
d = 50/2
d = 25 dimes
since 1 nickle = 5 cent, 1 dime = 10 cents we have:
5n + 10d = 5*50 + 10*25 = 250 + 250 = 500 cents = $5
the total value of the coins that Lucas dumped out of his piggy bank is $5.