Sam received $1120 interest from his 4 year investment at 3.5% p. a. simple interest. how much did sam invest? .

$8000

Step-by-step explanation:

The method for calculating simple interest (I) is

I =

where P is the principal, R is interest rate, T is time in years

here I = 1120, R = 3.5, T = 4 and P is to be found, thus

1120 = ( multiply both sides by 100 )

3.5 × 4 × P = 112000

14P = 112000 ( divide both sides by 14 )

P = = $8000