NCERT Class XI Mathematics - Sequences and Series - Solutions
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Question : 64
Total: 106
The number of bacteria in a certain culture doubles every hour. If there were 30 bacteria present in the culture originally, how many bacteria will be present at the end of 2nd hour, 4th hour and nth hour?
Solution:
There were 30 bacteria present in the culture originally and it doubles every hour. So, the number of bacteria at the end of successive hours form the G.P. i.e., 30, 60, 120, 240, ...........
∴ Numbers of bacteria will be present at the end of
(i) 2nd hour is 30 × 22 = 120
(ii) 4th hour is 30 × 24 = 480
(iii) nth hour is 30 ×2 n ( 2 n )
∴ Numbers of bacteria will be present at the end of
(i) 2nd hour is 30 × 22 = 120
(ii) 4th hour is 30 × 24 = 480
(iii) nth hour is 30 ×
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