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## anonymous 5 years ago I asked this yesterday and had no replies. The gross national product of a certain country is N(t)=t^2+3t+121 billion dollars where t is the number of years after 1990. At what percentage rate will the GNP be changing with respect to time in 1995? I got 13%, is this correct?

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1. sgadi

given that t=5 so GNP=161 The rate of increase of GNP is $\frac{dGNP}{dt}=2t+3=13$ there fore percentage increase is $\frac{13}{161}100=8.0745\%$

2. anonymous

How do you get GNP=161

3. sgadi

I am sorry ..... i did a mistake GNP=t^2+3t+12=5^2+3*5+12=52 so, 13/52*100=25%

4. anonymous

the problem is t^2+3t+121 not 12 i took the derivative of this equation which is 2t+3 then t(5) then I get 13.

5. sgadi

then my first reply is correct .... GNP=t^2+3t+12=5^2+3*5+12=161 so, 13/161*100=8.0745%

6. anonymous

but where do you get 161

7. sgadi

from the given formula .... also given time = t= 1995-1990=5 gross national product (GNP) = t^2+3t+121 =5^2+3*5+121=161

8. anonymous

ok i guess i should replace the t(5) with the original problem and the problem after I take the derivative.

9. sgadi

yes ....

10. anonymous

Thank You

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