Mark is playing poker at a casino. Mark starts playing with 150 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?  Choices.
A) $1,960	B) $1,740	C) $1,540	D) $3,080	E) $2,100
Total chips 150   20% of $100 chips = 30 chips * $100 = $3,000   80% of $20 chips = 120 chips * $20 = $2,400   If x is the number of chips bet and y is the amount of chips remaining:   x + y = 150   y = 150 - x ~ (1)   [First round bet] + [Second round bet] = $3,000 + $2,400   [0.1x * $100 + 0.9x * $20] + [0.3y * $100 + 0.7y * $20] = $5,400   10x + 18x + 30y + 14y = 5400   28x + 44y = 5400 ~ (2)   Substitute (1) into (2) to solve for x:   28x + 44(150 - x) = 5400   28x + 6600 - 44x = 5400   16x = 1200   x = 75   Substituting x:   [First round bet] = [0.1x * $100 + 0.9x * $20] = 0.1(75)($100)+0.9(75)($20) = $750 + $1,350 = $2,100   Answer is $2,100
<result>E</result>
Mark is playing poker at a casino. Mark starts playing with 150 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?