Answer: Jack is 8 years old (option A)
Explanation:
Hi, to answer this question we have to write an equation using the information given:
- Twice Jack's age plus 5 is 21
Twice : Means that the age of jack (j) is multiplied by 2 (2j),
Plus 5: we have to add 5 (2j+5).
Is 21: all is equal to 21.
Mathematically speaking:
2j +5 =21
Solving:
2j =21-5
2j =16
j= 16/2
j=8
Option A). 8
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