Find the sum of all the multiples of 5 between 1 and 200
A. 2800 B. 4300 C. 3900 D. 3200
Correct Answer: C
Explanation
Multiples of 5 between 1 and 200 will be 5. 10. 15. \(20 .\) 195 and excluding 200 with first term a \(=5\) common difference \(d=10-5=5\) and the last term \(U_{i p}=195\). To obtain the number of terms n of the sequence. we IISC \(U_{n}=a+(n-1) d\) \(195=5+(n-1) 5\) \(195-5-5(n-1)\) \(\frac{190}{5}=\frac{5(n-1)}{5}\) \(11-1=38\) \(n=38+1=39\) since the sequence is an