0 votes 0 votes Digital Logic test-series + – nag.swarna asked Nov 16, 2018 nag.swarna 317 views answer comment Share Follow See all 5 Comments See all 5 5 Comments reply Show 2 previous comments Hemanth_13 commented Nov 16, 2018 reply Follow Share (14*15)/2 => 105 ? Gupta731 am I missing any count ? 0 votes 0 votes Gupta731 commented Nov 16, 2018 reply Follow Share Its $\frac{2^{2n}-2^{n}}{2}$ Put n=4. 0 votes 0 votes Hemanth_13 commented Nov 16, 2018 reply Follow Share My analogy was if A = 15 then we have 14 choices for B if A=14 then we have 13 choices for B similarly if we go if A=1 then we have 1 choice for B(which is zero) so 14+13+12+...+1=> (14*15)/2==>105 0 votes 0 votes Please log in or register to add a comment.