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20 coins, consisting of dimes and quarters.
if the values were switched, the difference would be 90 cents.
This is how i came up with my answer.
solving the system:
one equation describes the number of coins: x + y = 20
where x is the number of dimes and y is the number of quarters.
the other equation describes the amount of money:
(0.25x + 0.1y) - (0.1x + 0.25y) = 0.90
(0.25x + 0.1y) describes when the dimes are quarters and the quarters are dimes.
(0.1x + 0.25y) describes when the dimes and quarters are their original values.
The difference is supposed to be $0.90 or 90cents.
Therefore,
by the elimination method of solving a system of equations:
x + y = 20 #1
(0.25x + 0.1y) - (0.1x + 0.25y) = 0.9 #2
simplify #2 to become:
0.15x - 0.15y = 0.9 #3
x + y = 20 #1
0.15x - 0.15y = 0.9 #3
multiply #1 by 0.15:
0.15x + 0.15y = 3 #4
0.15x - 0.15y = 0.9 #3
add #4 and #3:
0.30x = 3.9
x = 13
therefore, the number of dimes that the man has is 13.
to find the number of quarters, x is evaluated in the 1st equation.
x + y = 20
13 + y = 20
y = 20 - 13
y = 7
This can be checked as follows.
13 dimes = 130 cents
7 quarters = 175 cents
total = 305 cents
13 quarters = 325 cents
7 dimes = 70 cents
total = 395 cents
The difference between the two is 90 cents.
Therefore, the man had 13 dimes and 7 quarters.
By the way, is this a question that you are doing in class, have the answer to and are seeing who can figure it out, or are you proposing it for another reason?
Addendum (by PatrickLMT): Actually, this question was featured in the February 26, 1974 comic strip "Peanuts." Peppermint Patty had this question in school and despaired of finding the answer.
What else can I help you with?
How many is 10 quarters and 7 dimes equal?
10 quarters = 250 cents (25 x 10) 7 dimes = 70 cents (7 x 10) 250 + 70 = 320 10 quarters and 7 dimes equal 320 cents. In other words, $3.20 or 3 dollars and twenty cents.
What is the value in cents of q quarters?
1 quarter = 25 x (1) cents 2 quarters = 25 x (2) cents 3 quarters = 25 x (3) cents 4 quarters = 25 x (4) cents . . . 'q' quarters = 25 x (q) cents
How many cents are in four quarters?
4 quarters = 1 dollar = 100 cents
How do you make 95 cents using quarters?
Well, honey, you could make 95 cents using quarters by using three quarters and one dime. That's 75 cents from the quarters and 10 cents from the dime, which adds up to 95 cents. Math can be a real gem sometimes, can't it?
How much is two quarters?
2 quarters would be 50 cents, since 1 quarter is 25 cents.
How do you spell 29.99?
$29.99 is spelled like this: twenty nine dollars and ninety nine cents. 29.99 as a whole number and decimal would be: twenty nine point ninety nine or twenty nine and ninety nine hundredths.
What is one third of eight hundred ninety dollars and twenty eight cents?
One third of eight hundred ninety dollars and twenty eight cents is two hundred ninety six dollars and seventy six cents. Math doesn't lie, honey. Just divide that amount by three and you've got your answer.
How Can you make twenty five cents with fifteen coins how?
you have 375 cents in quarters and give away 14 of them :)
How do you spell out 427.90?
The number 427.90 is "four hundred twenty-seven and ninety hundredths." In US currency, the value $427.90 is "four hundred twenty-seven dollars and ninety cents."
How do you write three thousand four hundred twenty seven and ninety cents?
Like this: $3,427.90
What nine coins can you use to make ninety-three cents and there are 2 more dimes than quarters?
2 quarters,4 dimes, and 3 pennies
How do you spell 28499.94?
The number is twenty-eight thousand four hundred ninety-nine and ninety-four hundredths. It would ordinarily be spoken as "twenty-eight thousand four hundred ninety-nine point nine four." The currency value $28,499.94 is "twenty-eight thousand four hundred ninety-nine dollars and ninety-four cents."
What is 23.90 in word form?
23.90 in word form is "twenty-three dollars and ninety cents." It's not rocket science, honey. Just say what you see.
How do I spell out 4598.26 dollars?
four thousand, five hundred and ninety-eight dollars and twenty-six cents
What is 394.27 in word form?
I would write it as three hundred ninety four point two seven. Or three hundred ninety-four and twenty-seven hundredths. The US currency value $394.27 is three hundred ninety-four dollars and twenty-seven cents.
How many is 10 quarters and 7 dimes equal?
10 quarters = 250 cents (25 x 10) 7 dimes = 70 cents (7 x 10) 250 + 70 = 320 10 quarters and 7 dimes equal 320 cents. In other words, $3.20 or 3 dollars and twenty cents.
What twenty coins make ninety three cents?
1 quarter 5 dimes 1 nickel 13 pennies
