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| Question 1180260:  Jake has decided to invest in three business ventures. The total cost of investing in all three ventures is $15,000. The combined investment in the first and third ventures is $7,000 more than the investment in the second venture. According to Jake's research, his investment in the first venture will triple after three years, and the investments in the other two ventures will double in the same period, making the total value of his investment $39,000.
 Jake's investment in the first venture is $?
 a. $6,000
 b. $8,000
 c. $9,000
 d. $10,000
 His investment in the second venture is $?
 a. $2,000
 b. $4,000
 c. $6,000
 d. $7,000
 And his investment in the third venture is $?
 a. $1,000
 b. $2,000
 c. $3,000
 d. $4,000
 
 Answer by mananth(16946)
      (Show Source): 
You can put this solution on YOUR website! Jake has decided to invest in three business ventures. The total cost of investing in all three ventures is $15,000. The combined investment in the first and third ventures is $7,000 more than the investment in the second venture. According to Jake's research, his investment in the first venture will triple after three years, and the investments in the other two ventures will double in the same period, making the total value of his investment $39,000.
 Let x,y,z be the investment in I , II, and III investment respectively
 x+y+z=15000 ----------------(1)
 x+z = y+7000 ----------------(2)
 x-y+z =7000  ----------------(3)
 3x +2y+2z =39000 -------------(4)
 Add 1&3
 2x+2z=22000
 x+z = 11000
 plug x+z in (2)
 x+z = y+7000
 11000 =y+7000
 y = 4000----------------II
 multiply (1) b7 2 and subtract (4)
 x+y+z=15000
 2x+2y+2z =30000
 3x +2y+2z =39000
 ----------------
 -x = -9000
 x=9000----------------------I
 z = 2000--------------------III
 First venture $9,000
 Second venture $4000
 Third venture $ 2000
 
 
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