Aptitude - Surds and Indices - Discussion
Discussion Forum : Surds and Indices - General Questions (Q.No. 10)
10.
(0.04)-1.5 = ?
Answer: Option
Explanation:
| (0.04)-1.5 = |  |
4 |  |
-1.5 |
| 100 |
| = | |
1 | |
-(3/2) |
| 25 |
= (25)(3/2)
= (52)(3/2)
= (5)2 x (3/2)
= 53
= 125.
Discussion:
27 comments Page 1 of 3.
Destello said:
3 years ago
Instead of getting 3/2 just do one thing:
(4/100) ^ -1.5.
: 1/25 ^-1.5.
Note that, power is m=negative so if you invert the Numerator and Denominator power gets changed, in this case, if you invert the 1/25 into 25 the power get positive.
So, (25) ^ 1.5.
(5^2) ^ 1.5.
The rule applied here, (5)^2*1.5 ==5^3.
And the answer is 125.
(4/100) ^ -1.5.
: 1/25 ^-1.5.
Note that, power is m=negative so if you invert the Numerator and Denominator power gets changed, in this case, if you invert the 1/25 into 25 the power get positive.
So, (25) ^ 1.5.
(5^2) ^ 1.5.
The rule applied here, (5)^2*1.5 ==5^3.
And the answer is 125.
(13)
Monisha said:
7 years ago
@All
According to me, the solution is;
(0.04)^-1.5 { since 0.2*0.2=0.04}
= (0.2)^2*(-1.5),
=(0.2)^ -3,
=( 1/8) ^-3,
= 8^3 {since reciprocal changes the sign in power}
=512.
I used to solve it in a different method. But why am I not getting the answer? Please someone sorts this out.
According to me, the solution is;
(0.04)^-1.5 { since 0.2*0.2=0.04}
= (0.2)^2*(-1.5),
=(0.2)^ -3,
=( 1/8) ^-3,
= 8^3 {since reciprocal changes the sign in power}
=512.
I used to solve it in a different method. But why am I not getting the answer? Please someone sorts this out.
Nomie said:
4 years ago
X^-1 can be return as 1/X,
it is basic which we have already studied in school.
(0.04)^-1.5 = 1/(0.04)^1.5 = 1/(4/100)^1.5.
= 1/(2^2/10^2)1.5,
=1/(2^3/10^3),
=10^3/2^3,
=125.
it is basic which we have already studied in school.
(0.04)^-1.5 = 1/(0.04)^1.5 = 1/(4/100)^1.5.
= 1/(2^2/10^2)1.5,
=1/(2^3/10^3),
=10^3/2^3,
=125.
(1)
Sundar said:
1 decade ago
It is very simple yar.
3/2 = 1.5
Using vulgar-fraction instead of decimal-value of the given numbers will be helpful for solving problems.
3/2 = 1.5
Using vulgar-fraction instead of decimal-value of the given numbers will be helpful for solving problems.
Sujanith said:
9 years ago
Hi guys please let me know if this method is right:
(0.04)^-1.5 = (4/100)^-1.5
=> (2^2/10^2)^-(3/2)
=> (2/10)^-3 = 1/125
=> 125
(0.04)^-1.5 = (4/100)^-1.5
=> (2^2/10^2)^-(3/2)
=> (2/10)^-3 = 1/125
=> 125
Sayan said:
3 years ago
But (25) ^1. 5 = 25 + 25^0. 5 = 25 + 5.
So, that will be equal to 30. So, why is the answer coming different?
So, that will be equal to 30. So, why is the answer coming different?
(1)
Chirag said:
7 years ago
No @Monisha.
Because on dividing 1 by 8 i.e. 1/8 doesn't give us 0.2. So, 1/8 is not equal to 0.2.
Because on dividing 1 by 8 i.e. 1/8 doesn't give us 0.2. So, 1/8 is not equal to 0.2.
Navneet said:
4 years ago
@Misbahul.
(1/25) ^3/25 the power 3/25 was in minus, so if we reciprocal it, we get (25) ^3/25.
(1/25) ^3/25 the power 3/25 was in minus, so if we reciprocal it, we get (25) ^3/25.
(1)
MOSES said:
1 decade ago
1.5 is the same as 1+0.5.
Now 0.5 = 1/2. Now 1+1/2 = 3/2.
I hope this is now clearer.
Now 0.5 = 1/2. Now 1+1/2 = 3/2.
I hope this is now clearer.
Revanasidda said:
7 years ago
How -3/2 changes to 3/2?
By the basic law of indices, ie x^-1 can be written as 1/x.
By the basic law of indices, ie x^-1 can be written as 1/x.
(1)
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