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Numerical Ability
Algebra
A marketing company devised a methodology of spreading its message through one another. One person can tell it to 3 persons in 4 minutes and these three persons tell the other three persons each in further 4 minutes and the process continues so on. How many minutes will it take to spread the message to 2187 persons.
a)48 minutes b)24 minutes c)32 minutes d)28 minutes
Read Solution (Total 2)
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- according to the given condition 3^1 + 3^2 + 3^3 + ........ = 2187
or 3(3^x - 1)/(3-1) = 2187
or 3(3^x - 1)/2 = 2187
or 3^x - 1 = 2187*2/3 = 4374/3 = 1458
or 3^x = 1459 so x = 6 to 7
so total time taken = (6to7)*4 = 24 to 28 min
but if we take only the last step persons then 3^x = 2187 so x = 7
so time = 7*4 = 28 min - 13 years agoHelpfull: Yes(6) No(2)
- Option d
1 person tells 3 persons in , 4 min
3p will tell to 3*3 =9 in, 4 min
9p will tell to 9*3= 27 in , 4 min
27p will tell to 27*3= 81 in , 4 min
81p will tell to 81*3= 243 in , 4 min
243p will tell to 243*3 = 729 in , 4 min
729p will tell to 729*3=2187 in , 4 min
therefore total time = 28 min
- 8 years agoHelpfull: Yes(2) No(0)
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