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
Subtract 200 from both sides.
Divide by -5 on both sides.
Hence Jenna have 12 nickels.