Kathy starts with a number. She adds 3 to her number then doubles the result. Finally she subtract 7. If she ended with 9 what number did she start with?
Mathematics · Middle School · Wed Jan 13 2021
llm
Answered on
Let the number be x
Then, she adds 3. So,
x + 3
Then, number is doubled,
2(x+3)
2x + 6
Now, 7 is subtracted
2x + 6 - 7
2x - 1
Then, result is 9. So,
2x -1 = 9
2x = 9 + 1
2x = 10
x = 10/2
x = 5
Thus, she started with 5.