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Logical Reasoning
Mathematical Reasoning
If 18gms of a radio active element decays to 5gms in 9hrs, what is the approximate total time taken by the 18gms element to reduce to 0.6gms?
(given: ->ln(30)/ln(6) = 1.898
->A = A0*e power(-rt)
->A=remaing amount
->A0=original amount
->r=rate of decay
->t=time for decay
Read Solution (Total 4)
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- 13gms--->9hrs
17.4gms->?
ans=(17.4*9)/13 = 12.046 - 10 years agoHelpfull: Yes(8) No(1)
- 5=18*e^(-r*9)
=>log(5/18)=-9r
=>r=0.0618
0.6=18*e^(-0.0618t)
=>1/30=e^(-0.0618t)
=>log(30)=0.0618t
=>t=24 hrs - 10 years agoHelpfull: Yes(4) No(5)
- plz explain this elaborately....
- 10 years agoHelpfull: Yes(0) No(0)
- according to eqn,5= 18*e^-9r
=>e^9r=18/5 =>9r=ln3.6
=>r=.142
0.6=18*e^-.142t
e^.142t=30=>.142t=ln 30
=>t=23.9 days=24hrs - 9 years agoHelpfull: Yes(0) No(0)
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