Devante invests $4000 in two different accounts. The first account paid 6 %, the second account paid 11 % in interest. At the end of the first year he had earned $320 in interest. How much was in each account? $
at 6 %

$
at 11 %

y=1600

x=2400

Step-by-step explanation:

x+y=4000

solve for a variable

x=4000-y

plug this into .06x+.11y=320 (the interest from account 1 + account 2 must equal 320)

.06(4000-y)+.11y=320

240-.06y+.11y=320

minus 240 both sides

-.06y+.11y=80

combine terms

.05y=80

divide by .05

y=1600

to find x you subtract 1600 from 4000 to get 2400

remember, your equation must be x+y=4000

x+1600=4000

-1600

x=2400

step-by-step explanation:

circumference divided by 3.141592654 then timesthe radius twice

delaney would like to make a 5lb nut mixture that is 60% peanuts and 40% almonds.

she has several pounds of peanuts and several pounds of a mixture that is 20% peanuts and 80% almonds.

let 'p' represent the number of pounds of peanuts needed to make the new mixture, and  

let 'm' represent the number of pounds of the 80% almond-20% peanut mixture.

:

p + m = 5

therefore

m = (5-p)

write an equation based on the percent of peanuts

1p + .2m = .6(5)

replace m with (5-p)

p + .2(5-p) = .6(5)

p + 1 - .2p = 3

p - .2p = 3 - 1

.8p = 2

p = 2/.8

p = 2.5 lbs of peanuts required

then

5 - 2.5 = 2.5 lbs of the peanut/almond mixture required

:

a) what is the system that models this situation?

p + m = 5

1p + .2m = .6(5)