Question 936727
The sum is 4n+3*(n-1)=4n+3n-3=375, where n is the amount of terms and 4 represents thee first term. The 3 represents the common difference.
if 4n+3n-3=375, that means 7n=375+3, which equals 7n=378. Then you get the answer n-378/7, or 54.