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A radioactive substance is subject to th...

A radioactive substance is subject to the law of natural decay `(dv)/(dt)=-kv` where v is the valume of the substance at time t and k is a positive constant. If 40% of the substance disappear in 25 years, find the time it takes to disappear 60% of the substance.

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The correct Answer is:
`(25(log5-log2))/(log5-log3)` years
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CHHAYA PUBLICATION-DIFFERENTIAL EQUATIONS OF THE FIRST ORDER AND FIRST DEGREE -PART -E
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  6. Show that, the equation of the curve passing through (1,0) and satisfy...

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  7. A curve passes through tha point (2,0) and satisfies the equation ydy+...

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  8. A motor boat is moving in a straight line. Its velocity is V when the ...

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  9. A particle starts from the origin and moves along a straight line. If ...

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  10. The velocity of a particle moving in a straight path is given by v=16t...

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  11. The acceleration of a particle moving along a straight line is (6t^(2)...

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  12. If the acceleration of a particle at time t seconds be 1.2t^(2)ft//s^(...

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  13. A particle starts form the origin with a velocity of 10 cm/s and moves...

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  14. A particle starts from the origin with a velocity of 2 cm/s and moves ...

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  16. A radioactive substance is subject to the law of natural decay (dv)/(d...

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  18. If the marginal revenue function is (15-2x-x^(2)), find total revenue ...

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  19. The marginal cost function of manufacturing x pairs of shoes is RS(6+1...

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