Till 10th minute number of counted notes =1500 3000=2n[2×148+(n−1)(−2)]=n[148−n+1] n2−149n+3000=0n=125,24n=125 is not possible. Total time =24+10=34 minutes.
A person is to count 4500 currency notes. Let an denote the number of notes he counts in the nth minute. If a1=a2=……=a10=150 and a10,a11,…… are in A.P. with common difference −2, then the time taken by him to count all notes is
Held on 30 Apr 2010 · Verified 6 Jul 2026.
34 minutes
125 minutes
135 minutes
24 minutes
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