Some times, we use a different future value factor such as $.$ we call this $i$ a simple interest rate. In this case, Future Value $=PV\{1+(it)\},$ where $i=$ annual simple interest rate, $t=$ time in years.

John deposits $$100$ at a simple interest rate of i per annum at time $0.$ At the end of $10$ years, he has $$150$ in his account. Determine $i.$

$($express your answer in percentage without $\%$ sign, for example, if the answer is $8\%,$ type $8)$

$*$Unless otherwise specified, it is assumed that the interest is a compound interest, not simple interest rate in this course.