Answer: a) Number of nickels, dimes, and quarters are 80, 120, 300 respectively.
b) The coins are worth of 91 dollars i.e. $91 in the piggy bank.
Explanation:
Since we have given that
For every 2 nickels there are 3 dimes ,
So, their ratio will be 2:3
and for every 2 dimes there are 5 quarters.\,
So, their ratio will be 2:5
Now, we'll first find the ratio of nickles to dimes to quarters i.e.
Nickle Dimes Quarters
2 3
2 5
So, it becomes ,
Nickle : Dimes : Quarters
2×2 : 3×2 : 3×5
4 : 6 : 15
Now, let the number of nickle be 4x
Let the number of dimes be 6x
Let the number of quarters be 15x
According to question,
![4x+6x+15x=500\\\\25x=500\\\\x=\frac{500}{25}=20](https://tex.z-dn.net/?f=4x%2B6x%2B15x%3D500%5C%5C%5C%5C25x%3D500%5C%5C%5C%5Cx%3D%5Cfrac%7B500%7D%7B25%7D%3D20)
So, number of nickels is given by
![4x=4\times 20=80](https://tex.z-dn.net/?f=4x%3D4%5Ctimes%2020%3D80)
Number of dimes is given by
![6x=4\times 20=120](https://tex.z-dn.net/?f=6x%3D4%5Ctimes%2020%3D120)
Number of quarters is given by
![15x=4\times 20=300](https://tex.z-dn.net/?f=15x%3D4%5Ctimes%2020%3D300)
As we know that
![1\ nickel=5\ cents\\\\1\ dime=10\ cents\\\\1\ quarter=25\ cents](https://tex.z-dn.net/?f=1%5C%20nickel%3D5%5C%20cents%5C%5C%5C%5C1%5C%20dime%3D10%5C%20cents%5C%5C%5C%5C1%5C%20quarter%3D25%5C%20cents)
So, According to our question, we get
![80\times 5+120\times 10+300\times 25=400+1200+7500=9100\ cents\\\\1\ cent=0.01\ dollar\\\\9100\ cents=9100\times 0.01\ dollars=91\ dollars.](https://tex.z-dn.net/?f=80%5Ctimes%205%2B120%5Ctimes%2010%2B300%5Ctimes%2025%3D400%2B1200%2B7500%3D9100%5C%20cents%5C%5C%5C%5C1%5C%20cent%3D0.01%5C%20dollar%5C%5C%5C%5C9100%5C%20cents%3D9100%5Ctimes%200.01%5C%20dollars%3D91%5C%20dollars.)
Hence,
a) Number of nickels, dimes, and quarters are 80, 120, 300 respectively.
b) the coins are worth of 91 dollars i.e. $91 in the piggy bank.