If
123=84
456=58
678=34
then 789=


a.17
b.18
c.19
d.20
e.21
f.22
g.23
h.24
i.25
j.26

• for
  123=1*10 2*9 3*8=10 18 24
  taking even digits=084=84
  
  456=4*10 5*9 6*8=40 45 48
  taking even digits=058=58
  
  678=6*10 7*9 8*8=60 63 64
  taking even digits=034=34
  
  for 789=7*10 8*9 9*9=70 72 81
  therefore taking last digits=021=21
  
  ans is option e
  i.e 21
• 9 years agoHelpfull: Yes(1) No(0)