Answer:
25 one-dollar coins, 16 half-dollar coins, and 164 quarters
Step-by-step explanation:
First, set up equations based on the information given:
![0.25q+0.50h+1.00d=74](https://tex.z-dn.net/?f=0.25q%2B0.50h%2B1.00d%3D74)
![\displaystyle{h=\frac{3}{5}d+1}](https://tex.z-dn.net/?f=%5Cdisplaystyle%7Bh%3D%5Cfrac%7B3%7D%7B5%7Dd%2B1%7D)
![q=4(d+h)](https://tex.z-dn.net/?f=q%3D4%28d%2Bh%29)
Then, substitute <em>q</em> in the first equation with the expression from the third equation:
![0.25[4(d+h)]+0.50h+1.00d=74\\1d+1h+0.50h+1.00d=74\\2d+1.5h=74](https://tex.z-dn.net/?f=0.25%5B4%28d%2Bh%29%5D%2B0.50h%2B1.00d%3D74%5C%5C1d%2B1h%2B0.50h%2B1.00d%3D74%5C%5C2d%2B1.5h%3D74)
Next, substitute <em>h</em> in that equation with the expression from the second equation:
![\displaystyle{2d+1.5(\frac{3}{5}d+1)=74}](https://tex.z-dn.net/?f=%5Cdisplaystyle%7B2d%2B1.5%28%5Cfrac%7B3%7D%7B5%7Dd%2B1%29%3D74%7D)
![2d+0.9d+1.5=74\\2.9d+1.5=74](https://tex.z-dn.net/?f=2d%2B0.9d%2B1.5%3D74%5C%5C2.9d%2B1.5%3D74)
Solve for <em>d</em>, the number of one-dollar coins:
![2.9d+1.5=74\\2.9d=72.5\\d=25](https://tex.z-dn.net/?f=2.9d%2B1.5%3D74%5C%5C2.9d%3D72.5%5C%5Cd%3D25)
Substitute 25 for <em>d</em> in the second equation to find <em>h</em>, the number of half-dollar coins:
![\displaystyle{h=\frac{3}{5}d+1}](https://tex.z-dn.net/?f=%5Cdisplaystyle%7Bh%3D%5Cfrac%7B3%7D%7B5%7Dd%2B1%7D)
![\displaystyle{h=\frac{3}{5}(25)+1}](https://tex.z-dn.net/?f=%5Cdisplaystyle%7Bh%3D%5Cfrac%7B3%7D%7B5%7D%2825%29%2B1%7D)
![h=15+1\\h=16](https://tex.z-dn.net/?f=h%3D15%2B1%5C%5Ch%3D16)
Substitute 25 for <em>d</em> and 16 for <em>h</em> in the third equation to find <em>q</em>, the number of quarters:
![q=4(d+h)\\q=4(25+16)\\q=4(41)\\q=164](https://tex.z-dn.net/?f=q%3D4%28d%2Bh%29%5C%5Cq%3D4%2825%2B16%29%5C%5Cq%3D4%2841%29%5C%5Cq%3D164)
Then, verify that the coins total $74:
![0.25(164)+0.50(16)+1.00(25)=74\\41+8+25=74\\74=74\\\text{Check.}](https://tex.z-dn.net/?f=0.25%28164%29%2B0.50%2816%29%2B1.00%2825%29%3D74%5C%5C41%2B8%2B25%3D74%5C%5C74%3D74%5C%5C%5Ctext%7BCheck.%7D)
Next, verify that the number of half-dollar coins is one more than three-fifths of the number of one-dollar coins:
![\displaystyle{h=\frac{3}{5}d+1}](https://tex.z-dn.net/?f=%5Cdisplaystyle%7Bh%3D%5Cfrac%7B3%7D%7B5%7Dd%2B1%7D)
![\displaystyle{16=\frac{3}{5}(25)+1}](https://tex.z-dn.net/?f=%5Cdisplaystyle%7B16%3D%5Cfrac%7B3%7D%7B5%7D%2825%29%2B1%7D)
![16 = 15 + 1\\16 = 16\\\text{Check.}](https://tex.z-dn.net/?f=16%20%3D%2015%20%2B%201%5C%5C16%20%3D%2016%5C%5C%5Ctext%7BCheck.%7D)
Finally, verify that the number of quarters is four times the number one-dollar and half-dollar coins together:
![q=4(d+h)\\164=4(25+16)\\164=4(41)\\164=164\\\text{Check.}](https://tex.z-dn.net/?f=q%3D4%28d%2Bh%29%5C%5C164%3D4%2825%2B16%29%5C%5C164%3D4%2841%29%5C%5C164%3D164%5C%5C%5Ctext%7BCheck.%7D)