数学题请教

Sedulously

12. rounded to 10,000. X = 140,000; Y= 80,000. What is X+Y rounded to
10,000 a) actual numbers of X and Y are within 2% of 140,000 and 80,000,
respectively. b) X rounds up and Y rounds down (not sure which one rounds up
which one rounds down)

himba

a)137200<x<142800,78400<y<81600,所以215600<x+y<224400，所以 rounded to 220000

b)135000<x<140000,80000<y<85000,215000<x+y<225000，所以 rounded to 220000

选D