Answer:
x = 13
Jack is 13 years old and Jill is 11 years old.
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Explanation:
x = Jack's age
x-2 = Jill's age, since she is 2 years younger than Jack
Add up the ages and set the sum equal to 24 to solve for x
x+(x-2) = 24
2x-2 = 24
2x = 24+2
2x = 26
x = 26/2
x = 13
Jack is 13 years old and his sister is x-2 = 13-2 = 11 years old
Check: 13+11 = 24, so the answer is confirmed.