You could take it to your belly duh
Do the south 64 and then the 21 you never the .43
You would first turn it into an improper fraction, to do this you leave the denominator(bottom number) then times it by your variable and add the numerator(top number)
Ex:
1 3/4x1/3= 7/12
0.4L = 400ml
Each student effectively adds 10ml of water so 22 students are adding 10ml of water each. Therefore, 22 x 10 = 220ml total in all the containers added by all 22 students
Water left = 400 - 220 = 180
The answer is B.
200 is the answer so it would equal to 2 hundreds