Discussion :: Surds and Indices - General Questions (Q.No.4)
| 4. | If 5a = 3125, then the value of 5(a - 3) is: |
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Answer: Option A Explanation: 5a = 3125
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5a = 55
a = 5.
5(a - 3) = 5(5 - 3) = 52 = 25.| Girish said: (Jun 18, 2011) | |
| Also 5a-3 = 5a/53 = 3125/125 = 25 | |
| Girish said: (Jun 18, 2011) | |
| Above can be read as 5^a-3 = 5^a/5^3 = 3125/125 = 25 | |
| Shridhar Naik said: (Sep 16, 2012) | |
| 5^(a-3)=5^a*5^(-3)=3125/125=25 | |
| Bisu said: (May 27, 2013) | |
| Also can be solved. 5^a = 3125. 5^(a-3) = ? ==>5^(a-3) = 5^a/5^3 = 3125/125 = 25. |
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| Veronika said: (Jan 11, 2017) | |
| I am very new to this, what does ^ mean? I really need help. |
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| Swapnil said: (Jan 12, 2017) | |
| 5 a-3 = 5^a/5^3. = 3125/125. = 25. |
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| Shalini said: (Apr 27, 2017) | |
| @Veronika: ^ means raise to the power, i.e. 5^a= 5 raise to the power a. |
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| Ayesha said: (May 9, 2017) | |
| Why in the question they have to ask 5a they should have directly written it as 5^a did they get the same meaning? Please, someone tell me. |
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| Babu Vijayendra Kumar said: (Jun 26, 2017) | |
| I'm not getting this, anybody explain the logic. | |
| Aditya said: (Jul 22, 2017) | |
| 5a=3125 we can write 3125 in 5 * 5 * 5 * 5 * 5 then we get 5 power 5 then put value. Then, we get 5 power 2 we get 25. |
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| Ramesha T S said: (Oct 15, 2017) | |
| 5^(a-3)=(5^a)/(5^3)=3125/(5*5*5) = 25. | |
| Mandeep Mehra said: (Sep 15, 2018) | |
| 5^a=3125. 5^a-3=5^a/5^3. 5^a/5^3=3125/125=25. |
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| Asra said: (Apr 13, 2019) | |
| How to get the value of a by 5^a= 3125? Someone please help. |
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| Dhika said: (May 15, 2019) | |
| Here, the value of 5^a=3125. | |
| Urvashi said: (Jul 22, 2020) | |
| Given that 5^a = 3125 5^a = (5*5*5*5*5) Since (5*5*5*5*5) = 3125. So, 5 power a = 5 power 5. Since bases are same! Then subtract 3 from each according to question! 5^(a-3) = 5^(5-3), 5^(a-3) = 5^2, 5^(a-3) = (5*5). 5^(a-3) = 25. |
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| Siddharth Sahu said: (Jul 24, 2021) | |
| The simple method is 5^a/5^3 = 3125/5^3. That is equal to 5^a-3=3125/125 = 25. |
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