The number of bacteria in a colony growing exponentially. at 4 pm yesterday the number of bacteria is 400.and at 6 pm yesterday it was 3600. how many bacteria in the colony at 7 pm?
option
a) 3600
b) 10800
c) 14400
d) 32400

• at 6 pm, n=2hr
  3600=400*(r)^n
  or 400*9=400*(r)^2
  or r=3
  so at 7 pm,n=3hr
  no. of bacteria=400*(r)^n=400*(3)^3=10800
  option(b)
• 11 years agoHelpfull: Yes(23) No(0)
• ans:b
  400 at 4pm
  3600=400*3^2 at 6pm
  400*3^3=10800 at 7pm
• 11 years agoHelpfull: Yes(10) No(1)
• Given:yesterday 4pm no of bacteria=400(400*3^0)
  let 5pm no of bacteria=1200(400*3^1)
  6pm no of bacteria=3600(400*3^2)
  so 7pm no of bacteria=10800(400*3^3)
  so answer is 10800
• 10 years agoHelpfull: Yes(1) No(1)
• ans:b
  400 at 4pm
  3600=400*3^2 at 6pm
  400*3^3=10800 at 7pm
• 11 years agoHelpfull: Yes(0) No(1)
• at 4 pm= 400 = 400
  at 6 pm= 3600= 400*3^2
  so at 7 pm= 10800= 400*3^3
• 11 years agoHelpfull: Yes(0) No(1)