Test Index

CGPSC Prelims CSAT 2015 Solved Paper 2

© examsnet.com

Question : 15 of 100

Marks: +1, -0

If

5^{a} = 3125

, then the value of

5^{(a - 3)}

is

625
25
5
225
None of these

Solution:

Concept:

If powers have the same base, equate the exponents.

Explanation:

Given

5^{a}=3125

.

Write

3125

as a power of

5

:

3125=5^5

.

So

5^a=5^5

.

Since bases are equal,

a=5

.

Now compute

5^{a-3}

:

5^{5-3}=5^2

.

5^2=25

.

Answer:

The value of

5^{a-3}

is

25

, so option B is correct.

© examsnet.com

Go to Question:

Prev Question

Next Question