(0.8)-5 / (0.4)-4
-4.2 / -3.6
4.2/3.6 = 42/36 = 7/6
Am I missing something in understanding the Q?
Powers
This topic has expert replies
Source: Beat The GMAT — Data Sufficiency |
-
vishubn
- Legendary Member
- Posts: 574
- Joined: Sun Jun 01, 2008 8:48 am
- Location: Bangalore
- Thanked: 28 times
i got he answer has 1/12.8
so i am sure it should be either A/B and the OA is B
and also out of curioisty i used a calculator to
the dvision of 5/64 and 1/12.8 and it is indeed true
but i dont know how to deduce in the form of answer chocies !!
Vishu
so i am sure it should be either A/B and the OA is B
and also out of curioisty i used a calculator to
the dvision of 5/64 and 1/12.8 and it is indeed true
but i dont know how to deduce in the form of answer chocies !!
Vishu
-
Morgoth
- Master | Next Rank: 500 Posts
- Posts: 316
- Joined: Mon Sep 22, 2008 12:04 am
- Thanked: 36 times
- Followed by:1 members
(0.8)-5 / (0.4)-4vishubn wrote:(0.8)-5 / (0.4)-4 =
A. 3/32
B. 5/64
C. 1/2
D. 1
E. 2
i solved til lend but not able to relate it to the answer choices
vishu
(0.8)-5 = 1/0.8^5 = 1/ (8/10)^5
(0.4)-4 = 1/0.4^4 = 1/(4/10)^4
1/ (8/10)^5 / 1/(4/10)^4 = (4/10)^4 / (8/10)^5
4^4 / 1 / (8)^5 / 10 = 10/(2^4 * 8) = 10/ (16*8) = 10/128 = 5/64.
Hope this helps.
-
Morgoth
- Master | Next Rank: 500 Posts
- Posts: 316
- Joined: Mon Sep 22, 2008 12:04 am
- Thanked: 36 times
- Followed by:1 members
I am not able to understand what have you done here.stop@800 wrote:(0.8)-5 / (0.4)-4
-4.2 / -3.6
4.2/3.6 = 42/36 = 7/6
Am I missing something in understanding the Q?
0.8^-5 = 1/0.8^5 how this can be -4.2. no sure.
I misunderstood power.Morgoth wrote:I am not able to understand what have you done here.stop@800 wrote:(0.8)-5 / (0.4)-4
-4.2 / -3.6
4.2/3.6 = 42/36 = 7/6
Am I missing something in understanding the Q?
0.8^-5 = 1/0.8^5 how this can be -4.2. no sure.
As "^" was missing so I took it as just a subtraction
So stupid mistake
