The 3rd and 12th terms of an arithmetic progression are 12 and -24 respectively. What is the 50th term?

• we know that
  nth term of an ap is
  an=a+(n-1)d
  where an= nth term
  a= first term
  d= difference
  case 1
  a3= a+(3-1)d=a+2d=12 -----(1)
  a12= a+11d= -24 ----- (2)
  2-1
  we get 9d=-36
  d=-4
  substituting value of d in (1)
  a3=a+2(-4)=>a-8=12
  =>a=20
  so 20 is the first term
  50th term
  a50= a+49d
  =20+49(-4)=-176
• 12 years agoHelpfull: Yes(3) No(0)
• answer is -176...first term is 20 and common difference is 4
• 12 years agoHelpfull: Yes(1) No(1)