a gym offers regular memberships for $80 per month and off-peak memberships for $60 per month. last month, the gym sold a total of 420 memberships for a total of $31,100. the following system of equations models this scenario: 80x 60y = 31,100 x y = 420 how many of the memberships sold were regular memberships?
o 125
o 140
o 235
o 295