Though it is possible to edit my earlier post, I will make a modification to my workings and highlight my mistakes in blue. Let’s learn from my mistake!
It is possible to solve this question using the number of ladies or guys on Saturday as a reference. Arosisi’s approach used the number of ladies attending the workshop on Saturday as a reference, that is 100%. My workings will be using the number of guys on Saturday as 100%.
The earlier post’s method is based on algebra. If it is not a suitable method, you can consider percentage method + model diagram in arosisi’s post
Let the number of male participants attending the workshop on Saturday be 100%.
Number of Guys : 100%
Number of Ladies: 100%-130
Number of Guys : 100% x 80% = 80%
Number of Ladies: (100% -130) x 120% = 120% – 156
Thus, on Sunday, the total number of participants = (120%-156)+80% → 574
200% → 574+156 = 730
100% → 365
Number of female participants on Saturday = 365 -130 = 235
Total number of participants on Saturday= 365 + 235 = 600
Total amount of money paid = (600 + 574) x $25