Keith has p pennies, n nickels, and d dimes in his pocket. The total number of coins is 9. The expression 0.01p+0.05n+0.10d represents the value of the coins, which is equal to $0.44. He has one more dime than nickels. How many pennies does Keith have? Keith has _____ pennies.

Respuesta :

he  has 4 pennies

2 nickels=10 cents

3 dime=30 cents

             20 cents

40 +4 pennies =44 cents

Answer:

Keith has 4 pennies, 3 dimes and 2 nickels.

Step-by-step explanation:

Let the pennies be = p

Let the nickels be = n

Let the dimes be = d

Total coins Keith has = 9

So, 1st equation form :

[tex]p+n+d=9[/tex]     ....(1)

Keith has one more dime than nickels, means [tex]d=n+1[/tex]   .....(2)

Total value of these coins is $0.44

So, third equation forms:

[tex]0.01p+0.05n+0.10d=0.44[/tex]   .....(3)

Substituting (2) in (1)

[tex]p+n+n+1=9[/tex]

[tex]p+2n=8[/tex]     .....(4)

Similarly substitution (2) in (3)

[tex]0.01p+0.05n+0.10(n+1)=0.44[/tex]

[tex]0.01p+0.05n+0.10n+0.10=0.44[/tex]

[tex]0.01p+0.15n=0.34[/tex]    ....(5)

Now multiplying (4) by 0.01 and subtracting by (5)

[tex]0.01p+0.02n=0.08[/tex] subtracting this from (5) we get

[tex]0.13n=0.26[/tex]

So, we get n = 2

[tex]p+2n=8[/tex]

[tex]p+2(2)=8[/tex]

[tex]p+4=8[/tex]

p = 4

[tex]p+n+d=9[/tex]

[tex]4+2+d=9[/tex]

[tex]6+d=9[/tex]

d = 3

-------------------------------------------------------------------------------------

Therefore, Keith has 4 pennies, 3 dimes and 2 nickels.