Calling all math people!!!!!!

[RockstarDMD]

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Whats up guys and gals. I need to know the simplest way to solve the following problem:

Big Lou has $7200 invested, part at 4% and the rest at 5%. If annual income from both investments is the same, what is the income from Big Lou's investment?

Thanks to all in advance.

 

[fancymylotus]

Whats up guys and gals. I need to know the simplest way to solve the following problem:

Big Lou has $7200 invested, part at 4% and the rest at 5%. If annual income from both investments is the same, what is the income from Big Lou's investment?

Thanks to all in advance.

not that i can solve that or anything,but im the ****** the plugs numbers into every single problem with any x's or y's to try to solve them...total ****** method of doing it,but it seems to work. okay now a math person should answer his question so i can figure it out too 🙂

 

[hpets]

Whats up guys and gals. I need to know the simplest way to solve the following problem:

Big Lou has $7200 invested, part at 4% and the rest at 5%. If annual income from both investments is the same, what is the income from Big Lou's investment?

Thanks to all in advance.

this is like one of the topscore problems.
let x=amount of interest at .04 percent
let 7200-x= amount of interest at .05 percent (since you do not want two variables, i.e. x and y).

set those two values equal to each other to find the interest since they are equal to each other. that will be the interest accumulated. but you need to multiply it (x) by 2 since you have two interest rates going on at the same time, the 4 and 5%

 

[Chga]

X+Y = 7200
.4X = .5Y which turns into (.4/.5)X= Y ultimately (4/5)X= Y
plug that into first equation
X+ (4/5)X=7200 so X= 4000
now plug 4000 for X into (4/5)X= Y
so Y = 3200
4000 is invested at 4% & 3200 is invested at 5%

4% of 4000 is 160 5% of 3200 is also 160
so total income is 320

 

[RockstarDMD]

Thank you both hpets and chga. Well done.