Pamela is 12 years older than jiri the sum of their ages is 78 what is jiri’s age

Jiri's age is 33 years old

Step-by-step explanation:

let Pamela's age be = x

let Jiri's age be = y

pamela is 12 years older than Jiri

x = 12+y

sum of their age is 78

x+y = 78

use the substitution method to solve this question

x = 12+y (1)

x+y = 78 (2)

substitute (1) into (2)

x+y = 78

12+y+y = 78

12+2y = 78

2y = 78-12

2y = 66

y = 33

1/4 because there is 4 grades.