# Aptitude - Surds and Indices - Discussion

### Discussion :: Surds and Indices - General Questions (Q.No.3)

3.

Given that 100.48 = x, 100.70 = y and xz = y2, then the value of z is close to:

 [A]. 1.45 [B]. 1.88 [C]. 2.9 [D]. 3.7

Explanation:

xz = y2 10(0.48z) = 10(2 x 0.70) = 101.40 0.48z = 1.40 z = 140 = 35 = 2.9 (approx.) 48 12

 Fazila said: (Nov 10, 2010) I think its something different method.

 Vignesh said: (Sep 26, 2011) This not the different one, as like a to the power m whole to the power of n=a to the power of m*n.

 Rajesh said: (Jan 20, 2012) Its very Simple. If Base Values are equal of both side than power's are equal.

 Adeyemi Raphael said: (Mar 5, 2012) Why do both side have to divided, not addtion, subtraction or mutplication to get final answer?

 Sagar said: (Jun 10, 2012) It is very easy to solve if you know Logarithm. Step1: Zlog(10^0.48)=2log(10^0.70) Step2: ZX0.48=2X0.70 (Log10=1) Step3: Z= 2.9

 Roseline Aderonke said: (Nov 7, 2013) The workings are well understood once it is strictly followed step by step.

 Sanjay said: (Aug 18, 2014) What is the appropriate meaning of 2^0.5?

 Nego said: (Aug 2, 2015) I'm a bit confused about this. Why is the y2 not (0.70*0.70), rather its (2*0.70)?

 Tulasi said: (Sep 10, 2015) 10^0.48 = x //given. 10^0.7 = y //given. x^z = (10^0.7)^2. Since (a^m)^n = a^(m*n) we get, (10^0.48)^z = 10^(z*0.48) and (10^0.7)^2 = 10^(0.7*2). Now, 10^(0.48*z) = 10^(0.7*2). Since bases are equal, equating powers we get: z*0.48 = 0.7*2. z = 140/48. z = 2.9166 which is approximately 2.9.

 Kumar Arpit said: (Oct 11, 2015) That seems correct to me. I think this is the correct way.

 Thiyaguaxrev4Fvtr said: (May 26, 2016) How to get the answer? Please explain me.

 Jaichu said: (Mar 7, 2017) Please explain me. 0.48z = 1.40. z =140/48. How could they multiply it?

 Aniket Gaikwad said: (Apr 22, 2017) Thanks @Tulasi.

 Akhila said: (Jun 14, 2018) @Jaichu. For both nums decimal at the same place. So, a decimal can be removed.

 Jesophat said: (Feb 1, 2019) 48/100 = 0.48z =1.4z.

 Naman said: (Feb 17, 2020) I cannot understand it.