.
The strategy is to choose a single major unknown variable;
then to express all other variables via the major one;
then to build an equation, and to solve it accurately.
The final step is to calculate all other unknowns, write the answer and to check it.
Let N be the number of nickels in the bank (MAJOR unknown variable).
Then the number of dimes is 5N;
the number of quarters is 2*dimes = 2*(5N) = 10N.
The "value" equation is
nickels + dimes + quarters = 915 cents, or
5N + 10*(5N) + 25*(10N) = 915,
5N + 50N + 250N = 915,
305N = 915 ====> N = = 3.
Thus there are 3 nickels in the bank.
Then the number of dimes is 5*3 = 15 and
the number of quarters is 2*15 = 30.
Check. 3*5 + 10*15 + 25*30 = 915 cents. ! Correct !
Answer. 3 nickels, 15 dimes and 30 quarters.
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There is entire bunch of lessons on coin problems
- 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
- Solving coin problems mentally by grouping without using equations
- 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.
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.