Each cell of a certain kind of bacteria produces two more cells. The life span of each cell is 10 minutes and each cell multiples only once in its life time, when it is exactly one minute old. If a new cell is placed in an empty box at time t = 0, then how many live cells will be there in the box just after t = 20 minutes?  Choose the correct choice from the following choices
A) 2048 × 1023	B) 1024 × 1023	C) (1024)²	D) 1023 × 1025	E) 1023 × 1026
see total cells created after   1min be 2^1   2min be 2^2   3 min be 2^3.......   thus after 20 min 2^20 will be created   now after 10 min 1 cell will die (2^0)   after 11 min 2 cells die (2^1)   similarly after 20 min 2^10 cells die   thus total cells remained=(2^20)-(1024)   or (1024)^2-1024   or1024*(1024-1)   i.e, 1024*1023   ANSWER:1024 × 1023
<result>B</result>
Each cell of a certain kind of bacteria produces two more cells. The life span of each cell is 10 minutes and each cell multiples only once in its life time, when it is exactly one minute old. If a new cell is placed in an empty box at time t = 0, then how many live cells will be there in the box just after t = 20 minutes?