QR- Destroyer - Percent Question

[belmont3]

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Amanda has $1200 and invests it in 2 different stocks, A and B. Stock A increases in value by 15% and stock B decreases by 18%. If she makes $114 total, how much did she invest in stock A?

a) $1000
b) $900
c) $700
d) $600
e) $200

Please provide full explanation with the solution. Thanks a lot!

 

[TheEpicFruitCake]

System of equations problem
1200 = A + B
114 = A * (0.15) - B * ( 0.18)
.........(increase) - (decrease)

OR
1200 = A + B
1314 = A * (1.15) + B * ( 0.82)

The quickest way to do this would be guess and check method because they give you the only 5 possible answers. Think logically, okay so I came out positive, so A must be bigger than B because I actually lost a higher % of B than gained of A.
Answer choices D and E are automatically wrong.

 

[belmont3]

System of equations problem
1200 = A + B
114 = A * (0.15) - B * ( 0.18)
.........(increase) - (decrease)

OR
1200 = A + B
1314 = A * (1.15) + B * ( 0.82)

The quickest way to do this would be guess and check method because they give you the only 5 possible answers. Think logically, okay so I came out positive, so A must be bigger than B because I actually lost a higher % of B than gained of A.
Answer choices D and E are automatically wrong.

Got it. Thank you so much 🙂