Mr. Johnson has $15,000 to invest. Part of it is put in the bank at 4 percent, and part he puts in a savings and loan at 7 percent. If his yearly (simple) is $951, how much did he invest at each rate?

$3300 at 4%

$11700 at 7%

Step-by-step explanation:

Total investment = $15000

Total simple interest on investment = $951

Investment A:

Rate = 4% =0.04

Investment B:

Rate = 7% =0.07

Simple interest (S. I) = principal * rate * time

(S. I on investment A + S. I on investment B)

Let principal amount in investment A = A

principal amount in investment B = B

(A * 0.04 * 1) + (B * 0.07 * 1) = $951

0.04A + 0.07B = $951 - - - - (1)

A + B = $15000 - - - - (2)

from (2)

A = 15000 - B

Substitute A = 15000 - B into (1)

0.04(15000 - B) + 0.07B = 951

600 - 0.04B + 0.07B = 951

600 + 0.03B = 951

0.03B = 951 - 600

0.03B = 351

B = 351 / 0.03

B = $11700

From (2)

A + B = $15000

A + $11700 = $15000

A = $(15000 - 11700)

A = $3300

it is x=-4

step-by-step explanation: