Correct Option (B)
To determine the percentage by which number Y is less than number X, we first establish the values of X and Y relative to a third number Z.
- Assume the third number Z = 100.
- Number X is 20% less than Z:
- Number Y is 28% less than Z:
- The absolute difference between X and Y is:
- To calculate the percentage by which Y is less than X, the difference is expressed as a percentage of X:
X = 100−10020×100=80
Y = 100−10028×100=72
Difference = 80−72=8
Required percentage = 808×100=10%
Incorrect Options:
Options A (12%), C (9%), and D (8%) are incorrect. These values do not represent the accurate percentage by which Y is less than X. Option D (8%) represents the absolute difference between X and Y, not the percentage difference relative to X. The other incorrect options likely result from miscalculations or using an incorrect base for the percentage computation.