1. So basically all of the 4 people are 6 years older, so a total of 24 years older in total... so 20+24=44 years in total.
2. Each of them would be 4 years younger, which is 12 years younger in total... so 38-12=26 years in total.
3. Each year, each person gains one year and a total of 2 years gained a year... so 10/2=5 years until their combined ages are 40.
4. Basically the key is to find the total sum of their ages now... so you add 12 to 18 because that is their past age plus their 2 ages increasred by 6... thus the sum of their ages is 30. If Jeremy is twice as old as Randy, he has 2/3 of the total age and Randy 1/3, therefore, 2/3 of 30 is 20, and Jeremy is 20 years old.
5. Like the previous problem, the key is to find the total sum... so you subtract 14 and the total sum of their ages if 40, Tom is 4 times older than Kaden so therefore Tom is 32 years old.
Hopefully this helps you to understand the next... hundred problems