If 3/4 of the mineral deposits in a reservoir of water are removed every time a water filtration unit completes a cycle, what fraction of the total minerals present in the water will have been removed after 3 complete filtration cycles?
a. 63/64
b.25/32
c. 13/16
d. 9/32
e. 1/62
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Mineral Extracted
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kevincanspain
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A.
I did it by picking 1 as my initial number.
1-3/4 = 1/4 left after first pass
3/4 * 1/4 = 3/16 --> 1/4 - 3/16 = 1/16 after second pass
1/16 * 3/4 = 3/64 --> 1/16 - 3/64 = 1/64 left after third pass
how much removed in total = 1 - 1/64 = 63/64 = A
I did it by picking 1 as my initial number.
1-3/4 = 1/4 left after first pass
3/4 * 1/4 = 3/16 --> 1/4 - 3/16 = 1/16 after second pass
1/16 * 3/4 = 3/64 --> 1/16 - 3/64 = 1/64 left after third pass
how much removed in total = 1 - 1/64 = 63/64 = A
I or got to do the last step there and was getting 1/64Ashish8 wrote:A.
I did it by picking 1 as my initial number.
1-3/4 = 1/4 left after first pass
3/4 * 1/4 = 3/16 --> 1/4 - 3/16 = 1/16 after second pass
1/16 * 3/4 = 3/64 --> 1/16 - 3/64 = 1/64 left after third pass
how much removed in total = 1 - 1/64 = 63/64 = A
thanks ashish
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harshavardhanc
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Consider 100 as the initial quantity.mchaubey wrote:If 3/4 of the mineral deposits in a reservoir of water are removed every time a water filtration unit completes a cycle, what fraction of the total minerals present in the water will have been removed after 3 complete filtration cycles?
a. 63/64
b.25/32
c. 13/16
d. 9/32
e. 1/62
After three filtration the picture looks like :
100 -> 25 -> 25/4 -> 25/16
fraction left = 25/16 / 100 = 1/64.
therefore, the fraction removed = 1-1/64 = 63/64
Regards,
Harsha
Harsha
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Jeff@TargetTestPrep
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Since each filtration cycle removes 3/4 of the mineral deposits in the water, 1/4 of the mineral deposits will remain in the water. Thus, after 3 cycles, the amount of mineral deposits remaining in the water is 1/4 x 1/4 x 1/4 = 1/64. Thus, 1 - 1/64 = 63/64 of the mineral deposits will have been removed from the water.mchaubey wrote:If 3/4 of the mineral deposits in a reservoir of water are removed every time a water filtration unit completes a cycle, what fraction of the total minerals present in the water will have been removed after 3 complete filtration cycles?
a. 63/64
b.25/32
c. 13/16
d. 9/32
e. 1/62
Answer: A
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