Answer: 40000
Step-by-step explanation:
The formula to find the sample size is given by :-
, where p is the prior estimate of the population proportion.
Here we can see that the sample size is inversely proportion withe square of margin of error.
i.e. 
By the equation inverse variation, we have

Given :


Then, we have

Hence, the sample size will now have to be 4000.
\left[x \right] = \left[ \frac{13}{6}\right][x]=[613]
totally answer
If 21 is added to (+ 21) a number (x) the result (=) is 40 less than (- 40) twice the number (2x)
x + 21 = 2x - 40 Add 40 to both sides
x + 61 = 2x Subtract x from both sides
61 = x Switch the sides to make it easier to read
x = 61
If I read it right then 1. -147
2. -100