XAT 2015 — QA & DI Question 1
Arithmetic ProgressionEasy
What is the sum of the following series?
–64, –66, –68,……..….., –100
Answer & solution
- A
-1458
-1558
- C
-1568
- D
-1664
- E
None of the above
Solution
Number of terms = (100 – 64)/2 + 1 = 19
Sum = n/2 (a + an)
= 19/2 × (–64 –100) = –1558
Hence, option (b).