Answer:
A
Step-by-step explanation:
We are starting with 51
50x10=50
1x1=1
since there were 0.21 seconds, we first have to find the tenths place.
0.1x2=0.2
now that we found the tenths place, we need to find the hundredths place
0.01x1=1
FINAL ANSWER
(5 x 10) + (1 x 1) + (2 x 0.1) + (1 x 0.01)