alleryFind next: 1, 3, 6, 10, 15, ?
A21
B22
C20
D18
Answer & Solution
Correct answer: A. 21
1. Triangular numbers: T_n = n(n+1)/2.
2. Check: T_1=1, T_2=3, T_3=6, T_4=10, T_5=15.
3. Next is T_6 = 6*7/2 = 21.
4. So missing term is 21.
_Source: ICAI BoS Foundation Paper 3, Ch 9 'Series', p.4_
Keep practising Analogies
Browse all Analogies questions for CA Foundation, or explore more Quantitative Aptitude topics.
Related questions
Odd man out: APPLE, MANGO, BANANA, POTATOIn a series 2, 3, 5, 7, 11, 13, ?, the next prime isIf A=1, B=2, C=3, ..., the value of PEN isOdd man out: 9, 16, 24, 36, 49, 64Find next term: 8, 27, 64, 125, ?If the code for TEACHER is VGCEJGT, the code for STUDENT will beFind the missing term: 5, 9, 17, 33, 65, ?Find next term: 0, 7, 26, 63, 124, ?