How to extract columns then add new column by caculate in Linux

I have text file like below:

   ID   Grade1   Grade2  Grade3
 JK01       92       84      88
 JK02       87       80      93
 JK03       89       98      95

I want to extract specific column then add two column using awk.
Weight will from Grade2 *1.5+2,and Note is a specific number:17.
Desird Output like:

   ID   Grade2  Weight  Note
 JK01       84     134    17
 JK02       80     122    17
 JK03       98     149    17

I am using following command to achieve that

awk '{print $1,$3,$3*1.5+2, 17}' file.txt > file.tem.txt

But I got

ID Grade2 2 17
JK01 84 128 17
JK02 80 122 17
JK03 98 149 17

The header of Weight and Note not right.
And I also tried

awk -F, '{print $1,$3,"Weight", "Note"; next}
         {print $0,$2*1.5+2,17}' file.txt > file.tem.txt

form how to create column using awk with column name, still can’t get desird output.Any advice you can offer is appreciated.

>Solution :

check this out

awk 'BEGIN { OFS="\t" } NR==1 { print $1, $3, "Weight", "Note" } NR>1 { weight = $3 * 1.5 + 2; print $1, $3, weight, "17" }' file.txt

output

ID  Grade2  Weight  Note
JK01  84     128     17
JK02  80     122     17
JK03  98     149     17