So we know there are 12 brown ones
brown=12
50 more than 12 is the number of clear bottles so 50+12=62
brown=12
clear=62
30 numbers down from 62 is the number of green ones so 62-30=32
brown=12
clear=62
green=32
12+62+32=106
so Yoshiko collected 106 bottles
(5-3x+2y-2x+y)-(3x-7y+9)= (5-5x+3y)-(3x-7y+9)= 5-5x+3y-3x+7y-9= -8x+10y-4= 2(-4x+5y-2)
Cost of two tickets that Sheila paid to her friend = $ 90
Actual price of 1 ticket = $ 52.50
So, actual price of 2 tickets = 52 x 2 = 105
Hence, markdown or discount Sheila's friend gave her is =
105 - 90 = 15
The answer is $15.