| City | Percentage of persons not attending seminar | Percentage of male attending seminar | Male : Female (Not attending seminar) |
| A | 60% | 60% | 7 : 5 |
| B | 75% | 25% | 4 : 5 |
| C | 35% | 30% | 2 : 3 |
| D | 20% | 70% | 2 : 1 |
Let the total number of persons in city C = a
Number of persons not attending seminar = 0.35a
Number of females not attending seminar = 0.35 * 3/5 = 0.21a
0.21a = 420
a = 2000
Number of male not attending seminar = 2000 * 35/100 * 2/5 = 280
Difference = (420 - 280) = 140
m + 40 = 140
m = 100
Let, the total number of persons in city B = b
Number of persons not attending seminar = 0.75b
Number of females not attending seminar = 0.75b * 5/9
Now, 3.75b/9 = 750
b = 1800
Number of males not attending seminar = 0.75 * 1800 - 750 = 600
Required difference = 750 - 600 = 150
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