Aptitude - Surds and Indices - Discussion
Discussion Forum : Surds and Indices - General Questions (Q.No. 4)
4.
If 5a = 3125, then the value of 5(a - 3) is:
Answer: Option
Explanation:
5a = 3125 
5a = 55
a = 5.
5(a - 3) = 5(5 - 3) = 52 = 25.
Discussion:
18 comments Page 1 of 2.
Girish said:
1 decade ago
Also 5a-3 = 5a/53 = 3125/125 = 25
Girish said:
1 decade ago
Above can be read as 5^a-3 = 5^a/5^3 = 3125/125 = 25
Shridhar naik said:
1 decade ago
5^(a-3)=5^a*5^(-3)=3125/125=25
Bisu said:
1 decade ago
Also can be solved.
5^a = 3125.
5^(a-3) = ?
==>5^(a-3) = 5^a/5^3 = 3125/125 = 25.
5^a = 3125.
5^(a-3) = ?
==>5^(a-3) = 5^a/5^3 = 3125/125 = 25.
Veronika said:
9 years ago
I am very new to this, what does ^ mean?
I really need help.
I really need help.
Swapnil said:
9 years ago
5 a-3 = 5^a/5^3.
= 3125/125.
= 25.
= 3125/125.
= 25.
(1)
Shalini said:
8 years ago
@Veronika:
^ means raise to the power, i.e. 5^a= 5 raise to the power a.
^ means raise to the power, i.e. 5^a= 5 raise to the power a.
Ayesha said:
8 years ago
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.
Please, someone tell me.
Babu vijayendra kumar said:
8 years ago
I'm not getting this, anybody explain the logic.
(2)
Aditya said:
8 years ago
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.
Then, we get 5 power 2 we get 25.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers