1. Or

2. (1/7)*(1/6)

3. D

4. 

# P(B_1 = 1 and B_2=2 or B_1=2 and B_2=1) =  P(B_1 = 1 and B_2=2) + 
# P(B_1=2 and B_2=1) =

0.4*0.1 + 0.1*0.4

5. 

count <- 0
for (i in 1:nreps) {
   toss1 <- sample(0:1,1,replace=T)  
   # "replace" attribute doesn't matter here, coz only one sample is drawn
   toss2 <- sample(0:1,1,replace=T)
   if ( toss1+toss2 ==2  ) count <- count + 1
}
print(count/nreps)