Q: How many ways can you make 25 cents if you can use quarters, dimes, nickels or pennies?
Start with the largest value:
1 Quarter 1 way
2 Dimes, 1 Nickel You can stop here since it implies 2 ways.
2 Dimes, 0 Nickel ( which implies 5 pennies)
1 Dime, 3 Nickels , which implies 4 ways.
1 Dime, 2 Nickels ( 5 pennies)
1 Dime, 1 Nickel (10 pennies)
1 Dime, 0 Nickel ( 15 pennies)
0 Dime, 5 N, which implies 6 ways.
: , 4 N (5 pennies)
: , 3 N (10 pennies)
: , 2 N (15 pennies)
: , 1 N (20 pennies)
: , 0 N (25 pennies)
So altogether 13 ways.
Practice questions: (answers below)
Q 1 : How many ways can you make a. 15cents, b. 20cents, c. 30 cents if you can use quarters, dimes, nickels or pennies?
Q 2 : How many different combination of coins could a person have if she has exactly 21 cents?
Q 3 :Using nickels, dimes, quarters and/or half-dollars, how many ways can you make 75 cents?
Q 4: 20 coins of quarters and nickels add up to 4 dollars. How many nickels are there?
Q5: What is the least number of US coins to make changes possible from 1 to 99 cents inclusive? (half dollar is allowed)
Answers:
#1: a. 6 ways ; b. 9 ways; c 18 ways ;
#2: 9 ways
#3: 22 ways
#4: 5 nickels and 15 quarters
#5: 9 coins (1 half dollar, 1 quarter, 2 dimes, 1 nickel and 4 pennies)
Showing posts with label How many ways to make 25 cents. Show all posts
Showing posts with label How many ways to make 25 cents. Show all posts
Friday, May 11, 2012
Subscribe to:
Posts (Atom)