Counting of figures– Railway Reasoning (part – 1)

Total Questions: 50

21. Study the given pattern carefully and select the number that can replace the question mark(?) in it. [RRB NTPC 01/03/2021 (Morning)]

Correct Answer: (a) 21
Solution:

Logic: Product of number of sides + 1
5 × 3 + 1 = 16
6 × 5 + 1 = 31
3 × 4 + 1 = 13
Similarly,
4 × 5 + 1 = 21

22. Find the total number of straight lines in the following figure. [RRB NTPC 04/03/2021 (Morning)]

Correct Answer: (a) 11
Solution:

Horizontal = 4
Vertical = 4 , Diagonally = 3
Total straight lines = 4 + 4 + 3 = 11

23. How many squares are there in the following figure? [RRB NTPC 04/03/2021 (Evening)]

Correct Answer: (a) 34
Solution:

Total 34 squares are available.

24. Find the minimum number of straight lines in the following figure. [RRB NTPC 07/03/2021 (Evening)]

Correct Answer: (b) 12
Solution:If we look at the outer square, the minimum number of straight lines required will be = 6 ;
And for the inner square, the minimum number of straight lines required will be = 6 ;
So, the minimum number of straight lines in the given figure is 12 ;

25. Find the total no. of triangles in the given figure. [RRB NTPC 08/03/2021 (Evening)]

Correct Answer: (a) 10
Solution:

Total number of triangle
= (ABC) + (BDE) + (CFG) + (EHI) + (GJK) + (BLC) + (ABL) + (CME) + (ENG) + (GOI) = 10

26. Find the number of squares in the given figure. [RRB NTPC 09/03/2021 (Morning)]

Correct Answer: (a) 30
Solution:

Number of squares in each 1/4th part = 6 and 6 squares are there in the large square
Total number of squares = 6 × 4 + 6 = 30

27. Find the number of triangle in the figure given below: [RRB NTPC 11/03/2021 (Evening)]

Correct Answer: (b) 44 triangles
Solution:32 triangles = Square FGLE has 8 triangles, square GHKL, has 8 triangles, square HIJK has 8 triangles and square IBCJ has 8 triangles.
6 triangles = FAH, ABH, ABF, KCD, KDE, ECD 6 triangles = GEK, LHJ, KIC, FLH, GKI, HJB
Total triangles = 32 + 6 + 6 = 44

28. how many triangles are there in the given figure ? [RRB JE 22/05/2019 (Afternoon)]

Correct Answer: (c) 10
Solution:

Here triangles are = afg, gbj, jei, hid, fhc, ahe, fdb, bic, ajd, cge.
Hence 10 triangles are present in the given figure.

29. How many squares are there in the given figure? [RRB JE 22/05/2019 (Evening)]

Correct Answer: (d) 16
Solution:There are total 16 squares in the given figure i.e.
ABUK, LNRJ, KUHI, BCEU, NDFR, UEGH, LMTK, KTSJ, MNUT, TURS, NOPU, UPQR, ODEP, PEFQ,MOQS and ACGI.

30. How many squares are there in the given figure ? [RRB JE 23/05/2019 (Morning)]

Correct Answer: (c) 26
Solution: Trick :- firstly calculate all rows and columns and then (Cₙ × Rₙ ) + (Cₙ - 1 × Rₙ - 1 ) + ……… so on.
In the above question there are 3 rows and 5 columns hence
5 × 3 + 4 × 2 + 3 × 1 ⇒ 15 + 8 + 3 = 26