MathDB

14

Part of 2004 AMC 10

Problems(2)

Problem: 2004 AMC 10 #14

Source:

2/1/2007
The average value of all the pennies, nickels, dimes, and quarters in Paula's purse is 20 20 cents. If she had one more quarter, the average value would be 21 21 cents. How many dimes does she have in her purse? <spanclass=′latex−bold′>(A)</span> 0<spanclass=′latex−bold′>(B)</span> 1<spanclass=′latex−bold′>(C)</span> 2<spanclass=′latex−bold′>(D)</span> 3<spanclass=′latex−bold′>(E)</span> 4 <span class='latex-bold'>(A)</span>\ 0\qquad <span class='latex-bold'>(B)</span>\ 1\qquad <span class='latex-bold'>(C)</span>\ 2\qquad <span class='latex-bold'>(D)</span>\ 3\qquad <span class='latex-bold'>(E)</span>\ 4
Red &amp; Blue Marbles in a Bag

Source:

1/15/2009
A bag initially contains red marbles and blue marbles only, with more blue than red. Red marbles are added to the bag until only 1/3 1/3 of the marbles in the bag are blue. Then yellow marbles are added to the bag until only 1/5 1/5 of the marbles in the bag are blue. Finally, the number of blue marbles in the bag is doubled. What fraction of the marbles now in the bag are blue? <spanclass=′latex−bold′>(A)</span> 15<spanclass=′latex−bold′>(B)</span> 14<spanclass=′latex−bold′>(C)</span> 13<spanclass=′latex−bold′>(D)</span> 25<spanclass=′latex−bold′>(E)</span> 12 <span class='latex-bold'>(A)</span>\ \frac {1}{5}\qquad <span class='latex-bold'>(B)</span>\ \frac {1}{4}\qquad <span class='latex-bold'>(C)</span>\ \frac {1}{3}\qquad <span class='latex-bold'>(D)</span>\ \frac {2}{5}\qquad <span class='latex-bold'>(E)</span>\ \frac {1}{2}
ratio