Respuesta :
Answer:
3.85
Step-by-step explanation
7.7 divided by 2 = 3.85
So if you double 3.85 you get 7.7 and then add 20 to 7.7 then you get 27.7
Let the number they are thinking of be X.
They double x , which would be 2x.
They then add 20, which would be 2x +20
So you have 2x + 20 = 27.7
Now we can solve for x:
Subtract 20 from both sides:
2x = 7.7
Divide both sides by 2:
x = 7.7 / 2
x = 3.85
The original number was 3.85