There are 13 quarters in the jar.
Step-by-step explanation:
Given,
Number of coins in jar = 45 coins
Worth of coins = $5.90 = 5.90*100 = 590 cents
1 nickel = 5 cents
1 dime = 10 cents
1 quarter = 25 cents
Let,
Number of nickels = x
Number of dimes = y
Number of quarters = z
According to given statement;
x+y+z=45 Eqn 1
5x+10y+25z=590 Eqn 2
x+y=z+19 Eqn 3
Putting value of x+y from Eqn 3 in Eqn 2
[tex](z+19)+z=45\\z+19+z=45\\2z=45-19\\2z=26[/tex]
Dividing both sides by 2
[tex]\frac{2z}{2}=\frac{26}{2}\\z=13[/tex]
There are 13 quarters in the jar.
Keywords: linear equation, substitution method
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