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Mike invested a total of $25,000, some money in stocks and some money in bonds. The stocks earned 7% simple interest while the bonds earned 11% simple interest. Mike earned $2010 interest on his investments. How much money did he invest in bonds?

Respuesta :

Ashraf82

He invested $6500 in bonds

Step-by-step explanation:

The formula of the simple interest is I = Prt, where

  • P is the invested amount
  • r is the rate of interest in decimal
  • t is the time of investment

Assume that Mike invested $x in stocks and $y in bonds

∵ Mike invested $x in stocks

∵ Mike invested $y in bonds

∵ Mike invested a total of $25,000

∴ x + y = 25000 ⇒ (1)

∵ The interest rate of the stocks is 7%

∴ r of the stocks = 7 ÷ 100 = 0.07

∴ I (stocks) = x(0.07)(1)

∴ I (stocks) = 0.07x

∵ The interest rate of the bonds is 11%

∴ r of the bonds = 11 ÷ 100 = 0.11

∴ I (bonds) = y(0.11)(1)

∴ I (bonds) = 0.11y

∵ Mike earned $2010 interest on his investments

- Equate the sum of I (stocks) and I (bonds) by 2010

∴ 0.07x + 0.11y = 2010 ⇒ (2)

Now we have a system of equations to solve it

Multiply equation (1) by -0.11 to eliminate y

∵ -0.11x - 0.11y = -2750 ⇒ (3)

- Add equations (2) and (3)

∴ -0.04x = -740

- Divide both sides by -0.04

∴ x = 18500

- Substitute the value of x in equation (1) to find y

∵ 18500 + y = 25000

- Subtract 18500 from both sides

∴ y = 6500

∵ y represents the amount of money he invested in bonds

∴ He invested $6500 in bonds

He invested $6500 in bonds

Learn more:

You can learn more about the system of equations in brainly.com/question/6075514

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