here let total number of instruction is...100c

then 95 instruction will execute ideally (CPI=1) and rest 5 instruction will taken CPI=4...becoz evry branch instructon is executing like this....

S2 s2 s3 s4 s5

s1 s2 s3 s4 s5

s1 s2 s3 s4 s5....therefor CPI=4..

total time would be....95*1+5*4=115clock=115*4=460/100=4.6ns

then 95 instruction will execute ideally (CPI=1) and rest 5 instruction will taken CPI=4...becoz evry branch instructon is executing like this....

S2 s2 s3 s4 s5

s1 s2 s3 s4 s5

s1 s2 s3 s4 s5....therefor CPI=4..

total time would be....95*1+5*4=115clock=115*4=460/100=4.6ns