.
Mike has 185 pesos in 5-peso and 10-peso coins. He has one less 10 peso coin than 5-peso coins.
How many of each type of coin does he have?
~~~~~~~~~~~~~~~~
To solve the problem mentally, take off one 5-peso coin apart, for a minute.
You will have a collection of 180 pesos total, consisting of equal amount of 5-peso coins and 10-peso coins.
Group these coins in sets containing one 5-peso coin and one 10-peso coin.
Each set is worth 5+10 = 15 pesos, and the number of such groups is = 12.
Hence, there were 12 10-peso coins and 13 5-peso coins in the original collection. ANSWER
CHECK. 12*10 + 13*5 = 120 + 65 = 185 pesos, in total. ! Correct !
Solved.
----------------
On coin problems, see the lessons
- Coin problems
- More Coin problems
- Solving coin problems without using equations
- Kevin and Randy Muise have a jar containing coins
- Typical coin problems from the archive
- Three methods for solving standard (typical) coin word problems
- More complicated coin problems
- Advanced coin problems
- Solving coin problems mentally by grouping without using equations
- Non-typical coin problems
- Santa Claus helps solving coin problem
- OVERVIEW of lessons on coin word problems
in this site.
You will find there the lessons for all levels - from introductory to advanced,
and for all methods used - from one equation to two equations and even without equations.
A convenient place to quickly observe these lessons from a "bird flight height" (a top view) is the last lesson in the list.
Read them and become an expert in solution of coin problems.
Also, you have this free of charge online textbook in ALGEBRA-I in this site
- ALGEBRA-I - YOUR ONLINE TEXTBOOK.
The referred lessons are the part of this online textbook under the topic "Coin problems".
Save the link to this online textbook together with its description
Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson
to your archive and use it when it is needed.