Pamela is 10 years older than Jiri. The sum of their ages are 66, what is Jiri's age?

Step-by-step explanation:

Let's Jiri's age be "J" and Pamela's age be "P".

P = 9 + J (Pamela is 9 years older than Jiri.) ... equation 1

P + J = 107 (the sum of their ages is 107) ... equation 2

Put equation 1 into equation 2:

(9+J) + J = 109

9 + 2J = 109

2J = 109 - 9

2J = 100

J = 100/2

J = 50

Therefore, Jiri's age is 50.