ANSWER
4 and 16
Step-by-step explanation
Let the numbers be m and n.
Since one number is four times another number, we write;
![m = 4n...(1)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/v2m11fwlckcpf38mhi7u1yx9n7xmzcwh99.png)
The sum of the numbers is 20.
This gives us another equation:
![m + n = 20...(2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/3f4nn0t3odm4l2258jo0dwae3hozn99z5k.png)
We put equation (1) into equation (2) to obtain:
![4n + n = 20](https://img.qammunity.org/2020/formulas/mathematics/middle-school/g2522oopc6zsnjtpqqeqmqtby6sxy90kfj.png)
Simplify:
![5n = 20](https://img.qammunity.org/2020/formulas/mathematics/middle-school/snkq5s318krebfaxpcd1gys24vrx6u9szy.png)
Divide both sides by 5.
![n = 4](https://img.qammunity.org/2020/formulas/mathematics/middle-school/q5corsjp2f53b6pfvou4l2o161gb40s1ja.png)
We substitute n=4 into equation (1) to get;
![m = 4(4) = 16](https://img.qammunity.org/2020/formulas/mathematics/middle-school/79trf9dcrgqgpsblgb9x1vuiy9877zp58a.png)
Hence the numbers are 4 and 16.