SOLUTION: Solving Problems Using Linear Systems 4. Rehman invests his summer earnings of $3050. He invests part of the money at 8%/year, and the rest at 7.5%/year. After 1 year, these inves

Question 185477: Solving Problems Using Linear Systems
4. Rehman invests his summer earnings of $3050. He invests part of the money at 8%/year, and the rest at 7.5%/year. After 1 year, these investments earn $242 in simple interest. How much did he invest at each rate?
(answers are: $2650 at 8%/year and $400 at 7.5%/year, but i dont know how to solve it?)
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Rehman invests his summer earnings of $3050. He invests part of the money at 8%/year, and the rest at 7.5%/year. After 1 year, these investments earn $242 in simple interest. How much did he invest at each rate?
-----------------
Quantity Equation: x + y = 3050 dollars
Interest Equation:0.08x + 0.076y = 242
--------------------------------------------
Modify these equations so you can eliminate one of the variables:
80x + 80y = 244000
80x + 76y = 242000
------------------------
4y = 2000
y = 500 (amt invested at 7.6%
Substitute into x+y = 2050
x + 500 = 3050
x = 2550 (amt invested at 8%)
===================================
Cheers,
Stan H.
RELATED QUESTIONS
Alex invest his summer earnings of $3050. He invest part of the money at 8%/year, and the (answered by josmiceli,MathTherapy)

Alex invest his summer earnings of $3050. He invest part of the money at 8%/year, and the (answered by greenestamps)

Marco invests his summer earnings of $2440. He invests part of the money at 8% per year... (answered by mananth)

Alex invest his summer earnings of 43050. He invest part of the money at 8%/year, and the (answered by greenestamps)

Sergio invests part of his 90,000 PESOS at 4% and the rest at 3%. How much money is... (answered by mananth)

Sam invests the earnings of $3000 from her full-time job. She invests part of the money... (answered by richwmiller)

Solve this problem by using a two order system. A man invests $5,200, part at 4% and... (answered by nerdybill)

Billy invests $12,000. Part of it at 4% intrest and the rest at 5.5%. If his interest... (answered by JBarnum)

Solve Problems Using Linear Systems 14. Mengxi has $10 000 to invest. She invests part... (answered by badbadjoe)