A gym offers a 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. How many memberships sold were regular memberships?

A. 125

B. 140

C. 235

D. 295

Let us assume the number regular memberships = x

Let us assume the the number of off-peak membership = y

Then

x + y = 420

y = 420 - x

And

80x + 60y = 31100

Replacing the value of x from the first equation in the second equation, we get

80x + 60y = 31100

80x + 60 (420 - x) = 31100

80x + 25200 - 60x = 31100

20x = 31100 - 25200

20x = 5900

x = 5900/20

= 295

From the above deduction, we can conclude that 295 regular memberships were taken last month. The correct option among all the options that are given in the question is the fourth option or option "D".