Answer:
The parts of the number are 200 and 320
Explanation:
System of Equations
Suppose a and b are the two parts. They must meet two conditions:
![a+b=520\qquad\qquad [1]](https://img.qammunity.org/2021/formulas/mathematics/high-school/1p12kcpcyamswrg0s7zckny37a5t22thu9.png)
![\displaystyle (a)/(b)=(5)/(8)\qquad\qquad [2]](https://img.qammunity.org/2021/formulas/mathematics/high-school/b1b0hfxuizpwtbp1ntdv5zhfv4tdgd5ef3.png)
From [1], we have:
![b=520-a](https://img.qammunity.org/2021/formulas/mathematics/high-school/158gisi6me3xj1r5lf8dcyovznw4z6zqg2.png)
Replacing in [2]:
![\displaystyle (a)/(520-a)=(5)/(8)](https://img.qammunity.org/2021/formulas/mathematics/high-school/ec6xb8glzdinfkeumo4wlmjdm79x6iqfwo.png)
Cross-multiplying:
![8a=5*(520-a)](https://img.qammunity.org/2021/formulas/mathematics/high-school/j1qlxo94kwgaiw540cn5itveesrqlxumlu.png)
Operating:
![8a=2600-5a](https://img.qammunity.org/2021/formulas/mathematics/high-school/n3rj7kb97d1mtblb3ms2rmp68o4hr2d01r.png)
Joining like terms:
![13a=2600](https://img.qammunity.org/2021/formulas/mathematics/high-school/lu5j3ogpkc3t2w3oau8u43egtage63v953.png)
Solving:
![a=2600/13=200](https://img.qammunity.org/2021/formulas/mathematics/high-school/6uvru76lnlq7ybutz874w4sr4th6cfte8e.png)
a=200
Since:
![b=520-a\Rightarrow b=520-200](https://img.qammunity.org/2021/formulas/mathematics/high-school/ghei00le1a7x90n2a9sign551bln9t1dag.png)
b=320
The parts of the number are 200 and 320