Question 1165622
let r = Roy's present age
let k = Karla's
:
write an equation for each statemen
:
The sum of the ages of Roy and Karla is 91 years.
r + k = 91
Use this form for substitution
k = (91-r)
8years ago Roy’s age was 4 times karla's age. 
r - 8 = 4(k-8)
r - 8 = 4k - 32
r = 4k - 32 + 8
r = 4k - 24
 How old is Roy now?
replace k with (91-r)
r = 4(91-r) - 24
r = 364 - 4r
r + 4r = 364 - 24
5r = 340
r = 340/5
r = 68 yrs is Roy's age
:
:
Check solution:
 91 - 68 = 23 is Karla's age
"8 years ago Roy’s age was 4 times Karla's age."
68 - 8 = 4(23-8)
60 = 4(15)