Question

Kim is 5 years older than her brother Jack. If the sum of their ages is 21, find each of their ages.

Answer 1

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Answer:

• Kim is 13
• Jack is 8

Step-by-step explanation:

Let k represent Kim's age. Then Jack's age is k-5 and the total of their ages is ...

  k + (k -5) = 21

  2k = 26 . . . . . . . add 5, collect terms

  k = 13 . . . . . . . . . divide by 2; Kim's age

  k -5 = 8 . . . . . . . Jack's age

Kim is 13; Jack is 8.