Aptitude - Percentage - Discussion
Discussion Forum : Percentage - General Questions (Q.No. 9)
9.
| A student multiplied a number by | 3 | instead of | 5 | . |
| 5 | 3 |
What is the percentage error in the calculation?
Answer: Option
Explanation:
Let the number be x.
| Then, error = | 5 | x - | 3 | x = | 16 | x. |
| 3 | 5 | 15 |
| Error% = |  |
16x | x | 3 | x 100 |  % = 64%. |
| 15 | 5x |
Discussion:
134 comments Page 3 of 14.
Tufayel BD said:
3 years ago
Let number is 100.
Actual Multiplication = (100 *5)/3 = 500/3.
Student multiplied = (100 *3)/5 = 300/5.
Error,
= (500/3) - (300/5),
= (2500 - 900)/15,
= 1600/15.
%Error = (1600 *100 *3)/(15*500) = 64%.
Actual Multiplication = (100 *5)/3 = 500/3.
Student multiplied = (100 *3)/5 = 300/5.
Error,
= (500/3) - (300/5),
= (2500 - 900)/15,
= 1600/15.
%Error = (1600 *100 *3)/(15*500) = 64%.
(17)
SATHISHKUMAR R said:
4 years ago
Formula:
%of error = Question/comparison value * 100.
Here the question is finding an error.
Comparison is the true value.
3/5 x-5/3 x = 16/15 (LCM)/x means unknown value.
16/15 /(5/3) *100 = 64%.
%of error = Question/comparison value * 100.
Here the question is finding an error.
Comparison is the true value.
3/5 x-5/3 x = 16/15 (LCM)/x means unknown value.
16/15 /(5/3) *100 = 64%.
Gowtham said:
1 decade ago
30 is the common multiplying factor for the the both 5 and 3.
Then,
30*3/5=18,
30*5/3=50,
Make the answer for 100%
Then 18 became 36 and 50 to 100,
Subtract the final output to get an answer 64%.
Then,
30*3/5=18,
30*5/3=50,
Make the answer for 100%
Then 18 became 36 and 50 to 100,
Subtract the final output to get an answer 64%.
Vinay said:
1 month ago
Let's assume no is 30 it is divisible by both 5 and 3 ,and not get fractions.
No = 30.
3/5 * 30 =18
5/3 * 30 = 50
Error means = (difference/correct value ) * 100
Error = 32/50*100
Ans = 64.
No = 30.
3/5 * 30 =18
5/3 * 30 = 50
Error means = (difference/correct value ) * 100
Error = 32/50*100
Ans = 64.
(16)
P DHAMODARASAMY said:
6 years ago
Problem is 3/5 instead of 5/3.
So, we treat is as a ratio which is 3/5: 5/3,
Take lcm for 5 and 3, is 15,
Hence 3 * 15/5 : 5*15/3.
9:25. so the difference is 16.
Finally, 16 %of 25 is 64%.
So, we treat is as a ratio which is 3/5: 5/3,
Take lcm for 5 and 3, is 15,
Hence 3 * 15/5 : 5*15/3.
9:25. so the difference is 16.
Finally, 16 %of 25 is 64%.
Aditya said:
8 years ago
Easier method. Think of a number divisible by both 5 and 3. Let's say x=15.
True Value = (5/3)*15 = 25.
Wrong Value = (3/5)*15 = 16.
Now calculate the error : 9/25 * 100.
64% is correct.
True Value = (5/3)*15 = 25.
Wrong Value = (3/5)*15 = 16.
Now calculate the error : 9/25 * 100.
64% is correct.
Gayathri S said:
5 years ago
5/3 - 3/5 =?
Let's multiply 3*5 =15 which is the LCM
Now multiply 15 with 5/3 and 3/5 :
(15* 5/3) - (15* 3/5) = (25 - 9) /15
*= 16/15.
Error % = (16/15 * 3/5 * 100)%
= 64%.
Let's multiply 3*5 =15 which is the LCM
Now multiply 15 with 5/3 and 3/5 :
(15* 5/3) - (15* 3/5) = (25 - 9) /15
*= 16/15.
Error % = (16/15 * 3/5 * 100)%
= 64%.
Harish said:
6 years ago
Assume the number to be multiplied as 30.
The actual value is (5/3*30) =50.
But his value is (3/5*30) =18.
So the error is 32.
Here, 50 is 100% then 32 is 64%.
Therefore error is 64%.
The actual value is (5/3*30) =50.
But his value is (3/5*30) =18.
So the error is 32.
Here, 50 is 100% then 32 is 64%.
Therefore error is 64%.
Srihari said:
1 decade ago
No need of taking x. The difference of two nos become 16/15.
Then the percentage of 16/15 in the true value 5/3 is 64%.
16/15
------ x 100 = 64%. Thats logic Jananipriya.
5/3
Then the percentage of 16/15 in the true value 5/3 is 64%.
16/15
------ x 100 = 64%. Thats logic Jananipriya.
5/3
Sreekutty said:
1 decade ago
Error %= error / true value
but, here.. error= true value-false value
ie., error=(5/3)-(3/5)=16/5
so the error % will be equal to (16/5)/(5/3)=64%
(since, true value is 5/3)
but, here.. error= true value-false value
ie., error=(5/3)-(3/5)=16/5
so the error % will be equal to (16/5)/(5/3)=64%
(since, true value is 5/3)
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