Question 618965
Let the age of John be: 7n
Let the age of Sally be: n
So the ages of John and Sally is: 7n + n
In 10 years their ages will be:
John 7n + 10
Sally n + 10
Therefore:
7n + 10 + n + 10 = 71

Combine like terms:
7n + n = 8n
10 + 10 = 20

8n + 20 = 71

Subtract 20 from each side of the equation:
8n + 20 - 20 = 71 - 20
20 - 20 = 0
71 - 20 = 51

Therefore:
8n = 51
Divide each side by 8
8n/8 = 51/8
n = 6 years 4 1/2 months
Sally is 6 years 4 1/2 months
John's age is: 7n
Therefore:
7(6years 4 1/2 months)
7 * 6 = 42 years
7 * 4 1/2 = 31 1/2 months
31 1/2 months = 2 years 7 1/2 months
John"s age:
42 years + 2 years 7 1/2 months = 44 years 7 1/2 months
Sally is 6 years 4 1/2 months
John is 44 years 7 1/2 months