Answer:
3.6399 = 3.640
Step-by-step explanation:

Rounding to nearest thousandth means rounding to 3 decimal place
(0 to 4) =round down
(5 to 9)= round up
You could solve this mathematically but i mean you could use your eyes.... Its most likely C
;)
Yes you do , i learned pythagorean theorem last year in pre-algebra
WT is white T shirts
BT is blue T shirts, and WT=3BT
WT+BT=48
3BT+BT=48
4BT=48
BT=12 so WT =3×12=36