The ratio of the lenght breadth of a room
is 7:5 find the lenght
of the room if the breadth is 10cm​

plz mark brainliest i took the test

ending amount = beginning amount / (2^n)

where "n" = number of half-lives (or elapsed time / half-life)

ending amount = 50 mg / (2 ^10 / 5.3)

ending amount = 50 mg / (2 ^ 1.8867924528)

ending amount = 50 m / 3.6981210597

ending amount = 13.5203794557 mg

or about 13.5 mg remain

source:  

the answer is  

d.

21

i did this one. so you should get it right.

answer is  

d.

all of the above

hope you get this right