Answer:
13
Step-by-step explanation:
For this problem, work backwards to determine what the starting number was. Take 3.5 and multiply it by 3 to get 10.5, then subtract 4 to get 6.5. Finally, multiply 6.5 by 2 to get the starting number, which is 13. To check your work, you can always take 13 and perform the operations to make sure you end up with 3.5.
Hopefully this helps- let me know if you have any questions!
