The most accurate way would be the fourth answer, because to estimate 66% of 47 you need to round both as closely as possible. 66% rounds closest to 2/3, and 47 is closest to 48
Here is your answer wish you good luck
I thought doubling everytime except for the number 19000 because if you do 250 × 2 = 500 so then you do 500×2=1000.