You put $400 in an account. The account earns $18 simple interest in nine months. What is the annual interest rate

6%

Step-by-step explanation:

Simple Interest formula:

S.I=P×R×T/100

where

S.I is simple interest

P is principle amount

R is Annual interest rate

T is time period

[usually represented as (number of months)/12]

so

$18=$400×R/100×9/12

simplify

$18=$3600R/1200

$18=$3R

so R=$18/$3

=6

Therefore,

The Annual Interest Rate is 6%

answer: i guess 5 units?

step-by-step explanation: