Given data:
Ticket price = 400
Decrease in price = p%
Number of people = 3
Money spent = 1504
P% can be written as p/100
New ticket price = 400 - (400 x p/100)
Money spent = New ticket price x no. of people
1504 = [400 - (400 x p/100)] x 3
Taking 3 on the other side
1504/3 = 400 - (400 x p/100)
Taking 400 on other side
1504/3 - 400 = 400 x p/100
Can be written as (400/100)*p
101.333333333 = (400/100)*p
Taking (400/100) on other side, taking reciprocal.
101.333333333 x 100/400 = p
25.3333333332 = p
Rounding to two decimal place
p = 25.33
The ticket price decreases by 25.33%.