501 Questions To Master GED Test Mathematics_pag126

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501 Questions to Master the GED® Mathematical Reasoning Test
 179. The correct answer is choice a. The remaining amount to be 
deposited into the savings account is 6,500 – x. Multiply each 
of these amounts by the respective interest rate, add the result-
ing expressions, and set it equal to $100.50. Doing so yields this 
expression. 
 Choice b is incorrect because the right side should equal $100.50. 
 Choice c is incorrect because the coefficients on the left side show 
the interest rates but should show the total of the principal and the 
interest. 
 Choice d is incorrect because the quantity x – 6,500 should be 
6,500 – x. The coefficients on the left side show the interest rates 
but should show the total of the principal and the interest. 
 180. The correct answer is choice a. Let x be the number of quarters 
in the collection. There are x – 2 nickels and 2x + 1 dimes. Multiply 
each quantity by the value of 
the type of coin, sum these totals, and set it equal to 3.50: 
 0.05(x – 2) + 0.10(2x +1) + 0.25x = 3.50
 0.50x – 0.10 + 0.10 = 3.50
 x = 7
 There are 7 – 2 = 5 nickels. 
 Choice b is incorrect because this is the number of quarters. 
 Choice c is incorrect because this is twice the number of quarters; 
the number of nickels is 2 less than the number of quarters. 
 Choice d is incorrect because this is the number of dimes. 
 181. The correct answer is choice a. Start by multiplying the two 
binomials inside the brackets, and then square the resulting quan-
tity: [(1 – 3x2)(1 + 3x2)]2 = [1 – 9x4]2 = 1 – 9x4 – 9x4 + 81x8 = 1 – 18x4 
+ 81x8. 
 Choice b is incorrect because you forgot to include the middle 
term (involving the x4 terms), and the sign of the x8 term should 
be positive. 
 Choice c is incorrect because the exponent of the highest-degree 
term should be 8, not 6. 
 Choice d is incorrect because when you FOIL the binomials inside 
the brackets, you should get 1 – 9x4, not 1 – 6x4. Then, when you 
squared 1 – 6x4, you forgot the middle term. 
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