"Published in Vacaville, California, USA"
A man has 14 coins in his pocket, all of which are dimes and quarters. If the total value of his change is $ 2.75, how many dimes and how many quarters does he have?
Solution:
From the description of a given word problem, it is an application of linear equation with two equations, two unknowns.
Let x = be the number of dimes or 10 cent coins
y = be the number of quarters or 25 cent coins
From the statement "A man has 14 coins in his pocket, all of which are dimes and quarters.", then the working equation is
From the statement "If the total value of his change is $ 2.75,..", then the working equation is
Hence, the working equations for the given problem are
From the first equation,
Substitute the value of y to the second equation, we have
Substitute the value of x to any of two equations, we have
Therefore, there are 5 coins of dime and 9 coins of quarter in his pocket.
Check:
