Question 72017
How much interest will Ms. Williams earn if she invests $550 at 5% for 6 years.
If invested at simple interest: Prt= 550(0.06)6=$198.00
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The next one is,In the year 2010,  6.7% of the US population is projected to be under the age of 5.If the population will be about 298 million,about how many people will be in this age range?  Round your answer to the nearest ten thousand.
0.067*298 million = 19.966 million
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The third one is,The cost of a computer decreases from $1500 to $1200 after 3 months.Find the percent decrease.
The decrease is $300
Converting to percent you get 300/1500 = 1/5 = 20%
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And the last one is,this one is really confusing,An internet company sells CDs for $10 and tapes for $8.In one hour they sold eight times as many CDs as tapes.If their sales totaled $704,how many CDs did they sell?

Let number of CD's sold be "8x" ; Value of these is 10*8x = 80x dollars
Number of tapes sold is "x" ; Value of these is 8x dollars
EQUATION:
value + value = 704 dollars
80x + 8x = 704
88x = 704
x=8 (number of tapes sold)
8x=64 (number of CD's sold)
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Cheers,
Stan H.