# I don't know what the path to Rbuildtools is for you.  
# Mine is
C:\\RBuildTools\\3.3\\bin
C:\\RBuildTools\\3.3\\gcc-4.6.3\\bin
## Look in your computer for these two equivalent directories; version number (3.3) might be different

### START .Rprofile  ***** the first character of the file name is a dot (period) *******
## So my .Rprofile would be 

rtools <- "C:\\RBuildTools\\3.3\\bin;C:\\RBuildTools\\3.3\\gcc-4.6.3\\bin;"
Sys.setenv(PATH=paste0(rtools,Sys.getenv("PATH"))
rm(rtools) ## please add this

### END .Rprofile

## NOW RESTART R
## 
## and check PATH

Sys.getenv("PATH")
[1] "C:\\R\\R-3.3.1\\bin\\x64;c:\\R\\R-3.3.1\\bin\\x64;
C:\\RBuildTools\\3.3\\bin;C:\\RBuildTools\\3.3\\gcc-4.6.3\\bin; ## THIS LINE
C:\\Program Files (x86)\\Intel\\iCLS Client\\;C:\\Program Files\\Intel\\iCLS Client\\;
C:\\WINDOWS\\system32;C:\\WINDOWS;C:\\WINDOWS\\System32\\Wbem;C:\\WINDOWS\\System32\\WindowsPowerShell\\v1.0\\;
C:\\Program Files (x86)\\Common Files\\lenovo\\easyplussdk\\bin;
C:\\Program Files (x86)\\Intel\\Intel(R) Management Engine Components\\DAL;
C:\\Program Files\\Intel\\Intel(R) Management Engine Components\\DAL;
C:\\Program Files (x86)\\Intel\\Intel(R) Management Engine Components\\IPT;
C:\\Program Files\\Intel\\Intel(R) Management Engine Components\\IPT;
C:\\Program Files\\Git\\cmd;C:\\Users\\kyleb\\AppData\\Local\\Microsoft\\WindowsApps;"