Question

Kathi starts with a number . She adds 3 to her number, then doubles the result. Finally , she subtracts 7. If she ended with 9, what number did she start with ?

Answer 1

The number she started with is 5.

Answer 2

Answer: The required number is 5.

Step-by-step explanation: Given that Kathi starts with a number, she adds 3 to her number and then doubles the result. Finally , she subtracts 7 and she ended with 9.

We are to find the number.

Let n represents the required number.

Then, according to the given information, we have

`2*(n+3)-7=9\\\\\Rightarrow 2(n+3)=9+7\\\\\Rightarrow 2(n+3)=16\\\\\Rightarrow n+3=(16)/(2)\\\\\Rightarrow n+3=8\\\\\Rightarrow n=8-3\\\\\Rightarrow n=5.`

Thus, the required number is 5.