A = {1, 3, 5, 7, 9} B = {2, 4, 6, 8, 10} C = {1, 5, 6, 7, 9} A ∩ (B ∪ C) =
vovikov84 [41]
A = {1, 3, 5, 7, 9}
B = {2, 4, 6, 8, 10}
C = {1, 5, 6, 7, 9}
(B ∪ C) = {1, 2, 4, 5, 6, 7, 8, 9, 10}
so
A ∩ (B ∪ C) = {1, 5, 7 , 9}
The length of the race is 5 kilometers.
5 kilometers equals 5000 meters.
Since Lana's avarege step length is about 0.5 meters, we need to divide 5000 by 0.5

Hence, Lana needs to take about
10000 steps.
It seems you tried to write √(-20)
use the fact tha -1 = i^2
Then, √(-20) = √(20i^2) =(√20) i = (√(5*4))i = 2√5 i = 2i√5, which seems to be what you tried to write in the option B.
Number 5 is muply by 2 and number 6 is added by 6