Find the sum of all positive multiples of 5 less than 100.
A. 925
B. 960
C. 950
D. 990
Answer: Option C
Solution(By Examveda Team)
Sum = 5 + 10 + 15 + 20 + .....+ 95 , It is an arithmetic progressionNumber of terms (n)
= $$\frac{{{\text{Last term }} - {\text{ First term}}}}{{{\text{Differnce}}}}$$ + 1
⇒ n = $$\frac{95 - 5}{5}$$ + 1 = 19
So, sum = $$\frac{n}{2}$$ [2a + (n - 1)d]
Here, a = 5, n = 19, d = 5
Sum = $$\frac{19}{2}$$ [10 + (19 - 1)5]
= 950
Related Questions on Number System
Three numbers are in ratio 1 : 2 : 3 and HCF is 12. The numbers are:
A. 12, 24, 36
B. 11, 22, 33
C. 12, 24, 32
D. 5, 10, 15
Join The Discussion