Mark is playing poker at a casino. Mark starts playing with 160 chips, 20% of which are $100 chips and 80% of which are $20 chips. For his first bet, Mark places chips, 10% of which are $100 chips, in the center of the table. If 70% of Mark's remaining chips are $20 chips, how much money did Mark bet?
Choose the correct choice from the following answers:  A) $1,960  B) $1,740  C) $1,540  D) $3,080  E) $2,240
Total chips 160   20% of $100 chips = 32 chips * $100 = $3,200   80% of $20 chips = 128 chips * $20 = $2,560   If x is the number of chips bet and y is the amount of chips remaining:   x + y = 160   y = 160 - x ~ (1)   [First round bet] + [Second round bet] = $3,200 + $2,560   [0.1x * $100 + 0.9x * $20] + [0.3y * $100 + 0.7y * $20] = $5,760   10x + 18x + 30y + 14y = 5760   28x + 44y = 5760 ~ (2)   Substitute (1) into (2) to solve for x:   28x + 44(160 - x) = 5760   28x + 7040 - 44x = 5760   16x = 1280   x = 80   Substituting x:   [First round bet] = [0.1x * $100 + 0.9x * $20] = 0.1(80)($100)+0.9(80)($20) = $800 + $1,440 = $2,240   Answer is $2,240
<result>E</result>
Mark is playing poker at a casino. Mark starts playing with 160 chips, 20% of which are $100 chips and 80% of which are $20 chips. For his first bet, Mark places chips, 10% of which are $100 chips, in the center of the table. If 70% of Mark's remaining chips are $20 chips, how much money did Mark bet?