$($b$)$ Develop a user defined function $$MySummer$$ that calculate the weighted average with the

equation, $=((63)+42+2)$

$=1$

$(2$

$=1+3).$

Use the values given on the sheet $$P$3$a$$ to test the function. Reminder: this function must have

two arguments, X$,$ and n

Use the values given on the sheet $"$P$3$a$"$ to test the function. Reminder: this function must have two arguments, X $,$ and n $.$