fozzzy wrote:
20 marbles were pulled out of a bag of only white marbles, painted black, and then put back in. Then, another 20 marbles were pulled out, of which 1 was black, afterwhich they were all returned to the bag. If the percentage of black marbles pulled out the second time represents their percentage in the bag, how many marbles in total does the bag currently hold?
A 40
B 200
C 380
D 400
E 3200
Please explain confuesed how to form an equation for this problem...
Ok. Lets do it with the help of ratio. 20 Black marbles in a bag of white marbles after 1st draw.
Second time, out of 20 there is one black marble. Ratio of Total:Black = 20:1
For every 1 black marble there are total of 20 marbles then
for 20 Black marbles we will have 20*20 = 400 Marbles in total.
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