Math Question - Algebra

Question

Mr. Geld has $50,000 to invest. Part of it is put in the bank at 6 percent, and part he puts in a savings and loan at 9 percent. If his yearly interest (simple) is $3660, how much did he invest at each rate?

Answer 1

The statement is unclear to me. I'm going to assume he puts part of the $50k into a 6% vehicle, and the rest into a 9% vehicle.

Let x be the amount in the 6%

Then $50k - x is the amount in the 9%

interest = rate*amount so

i_6% = 0.06*x

i_9% = 0.09*($50k - x)

total interest is $3.66k so

0.06x + 0.09($50k-x) = $3.66k

Solving for x, we get x=$28k,

so $50k - x = $22k.

He invested $22,000 at 9% and $28,000 at 6%.

Let's check our work:

22k*0.09 + 28k*0.06 = 3.66k <--- good