Chris, Alex and Jesse are all siblings in the same family. Alex is 5 years older than chris. Jesse is 6 years older than Alex. The sum of their ages is 31 years. How old is each one of them?
Set up the relational equations where a = Alex's age, c = Chris's aged and j = Jesse's age
Plug in (4) and (2) into (3)
a + (a - 5) + (a + 6) = 31
Combine like terms:
3a + 1 = 31
Subtract 1 from each side
3a = 30
Divide each side by 3
a = 10
Plug in 1 = 10 into Equation (4)
c = 10 - 5
c = 5
Now plug 1 = 10 into equation (2)
j = 10 + 6
j = 16
Set up the relational equations where a = Alex's age, c = Chris's aged and j = Jesse's age
- a = c + 5
- j = a + 6
- a + c + j = 31
- Rearrange (1) in terms of c: c = a - 5
Plug in (4) and (2) into (3)
a + (a - 5) + (a + 6) = 31
Combine like terms:
3a + 1 = 31
Subtract 1 from each side
3a = 30
Divide each side by 3
a = 10
Plug in 1 = 10 into Equation (4)
c = 10 - 5
c = 5
Now plug 1 = 10 into equation (2)
j = 10 + 6
j = 16