we have
Chem 140 ------> 3 credits
A- ------> 3.7
multiply 3.7 by the number of credits
so
3.7(3)=11.1
Chem 141 ------> 2 credits
B------> 3
3(2)=6
Engl 101 -----> 5 credits
A- --------> 3.7
3.7(5)=18.5
Math 151 ------> 5 credits
B+ ------> 3.3
3.3(5)=16.5
Adds the numbers
11.1+6+18.5+16.5=52.1
Now divided by the total credits
3+2+5+5=15
therefore
GPA=52.1/15=3.47
GPA=3.47