document.write( "Question 1186907: The world production of gold from 1970 to 1990 can be modelled by G = 5.2t 2 - 76t + 1492, where G is the
\n" ); document.write( "number of tonnes of gold and t is the number of years since 1970, t = 1 for 1971 and so on.
\n" ); document.write( "a. What was the most amount of gold mined in one year?
\n" ); document.write( "b. How much gold was mined in 1978? \n" ); document.write( "

Algebra.Com's Answer #851860 by ikleyn(52782) $\"\"$ $\"About$

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\n" ); document.write( "The world production of gold from 1970 to 1990 can be modelled by G = 5.2t 2 - 76t + 1492,
\n" ); document.write( "where G is the number of tonnes of gold and t is the number of years since 1970,
\n" ); document.write( "t = 1 for 1971 and so on.
\n" ); document.write( "a. What was the most amount of gold mined in one year?
\n" ); document.write( "b. How much gold was mined in 1978?
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\n" ); document.write( "\n" ); document.write( "The problem's formulation is not perfect for a Math problem.\r
\n" ); document.write( "\n" ); document.write( "I would edit it in this way (my editing is underlined and crossed) \r
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document.write( "    The world annual production of gold from 1970 to 1990 can be modelled by G = 5.2t 2 - 76t + 1492, \r\n" );
document.write( "    where G is the number of tonnes of gold produced per year and t is the number of years since 1970, \r\n" );
document.write( "    t = 1 for 1971 and so on.\r\n" );
document.write( "    a. What was the  greatest amount of gold mined in one year?\r\n" );
document.write( "    b. How much gold was mined in 1978?\r\n" );
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\n" ); document.write( "\n" ); document.write( "In the post by @CPhill, in the part (a), his reading of the problem is INCORRECT; his interpretation of the problem
\n" ); document.write( "is incorrect; his treating of the problem is incorrect; his solution is incorrect and his answer is incorrect.\r
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\n" ); document.write( "\n" ); document.write( "@CPhill focused on the minimal amount of the gold mined in one year, while the problem in part (a) asks
\n" ); document.write( "about the maximum amount.\r
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\n" ); document.write( "\n" ); document.write( "For it, the amount at the ends of the time interval should be considered.\r
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document.write( "If you do it, you will find that the greatest amount of the mined gold was achieved in the year 1990 (t = 20),\r\n" );
document.write( "and this greatest amount was\r\n" );
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document.write( "    G(20) = 5.2*20^2 - 76*20 + 1492 = 2052 tons.\r\n" );
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