Justin is exchanging dollars for rolls of quarters and rolls of dimes at a bank. Each roll of quarters has a value of $10 and each roll of dimes has a value of $5. He exchanges $90 and receives 11 rolls of coins. How many of each type of roll of coins did he receive?

Well, it really depends but it could be 9 rolls of quarters, 5 rolls of quarters and 8 rolls of dimes, 4 rolls of quarters and 10 rolls of dimes, 3 rolls of quarters and 12 rolls of dimes, etc.

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chisnau chisnau · Answer 2 · 2019-09-09T22:45:18+02:00

Answer:

Justin got 7 rolls of quarters and 4 rolls of dimes.

Step-by-step explanation:

Let the roll of quarters be x

Let the rolls of dimes be y

As total money received is $90, the equation becomes;

[tex]10x+5y=90[/tex] .....(1)

And he got 11 roll of coins, so equation becomes;

[tex]x+y=11[/tex] or [tex]x=11-y[/tex] .... (2)

Substituting the value of x from (2) in (1)

[tex]10(11-y)+5y=90[/tex]

[tex]=> 110-10y+5y=90[/tex]

[tex]=> -5y=-110+90[/tex]

[tex]=> -5y=-20[/tex]

So, y = 4

As [tex]x=11-y[/tex]

So, [tex]x=11-4[/tex]

x = 7

Hence, Justin got 7 rolls of quarters and 4 rolls of dimes.