Question 210426
Sam is 10 years older than Jack. 
Twice Sam's age subtracted from 6 times Jack's age is 7 more than Jack's age.
 Find Jack and Sam's age.
:
Let j = Jack's age
Let s = Sam's age
:
"Sam is 10 years older than Jack."
s = j + 10
:
"Twice Sam's age subtracted from 6 times Jack's age is 7 more than Jack's age."
6j - 2s = j + 7
6j - j = 2s + 7
5j = 2s + 7
:
 Find Jack and Sam's age.
:
Substitute (j+10) for s in the above equation
5j = 2(j+10) + 7
5j = 2j + 20 + 7
5j - 2j = 27
3j = 27
j = {{{27/3}}}
j = 9 yrs is Jack's age
:
s = j + 10
s = 9 + 10
s = 19 yrs is Sam's age
:
:
Check solution in the statement:
"Twice Sam's age subtracted from 6 times Jack's age is 7 more than Jack's age."
-2(19) + 6(9) = 9 + 7
-38 + 54 = 16