Given:
Total number of coins = 20
Total cost of nickel and dime = $1.40
To find:
The number of nickels.
Solution:
Let the number of nickels be "n" and number of dimes be "20 - n".
Value of nickel = 5 cents
Value of dime = 10 cents
$1.40 = 140 cents
Cost of nickel + Cost of dime = $1.40
[tex]5(n) +10(20-n)=140[/tex]
[tex]5n+200-10n=140[/tex]
[tex]200-5n=140[/tex]
Subtract 200 from both sides.
[tex]200-5n-200=140-200[/tex]
[tex]-5n=-60[/tex]
Divide by -5 on both sides.
[tex]$\frac{-5n}{-5} =\frac{-60}{-5}[/tex]
[tex]n=12[/tex]
Hence Jenna have 12 nickels.
