Question: If A = 2, B = 4, C = 6, D = 8, E = 10 and so on, what is the meaning of following number 40, 18, 14, 10, 36

Solution:
Given,
A = 2, B = 4, C = 6, D = 8, E = 10.......

∴ Each code = Letter position × 2

So
40 ÷ 2 = 20 → T
18 ÷ 2 = 9 → I
14 ÷ 2 = 7 → G
10 ÷ 2 = 5 → E
36 ÷ 2 = 18 → R

the meaning of following number = TIGER

Question: In a class, 30 students play basketball, 20 students play volleyball, and 8 students play both. 12 students play neither basketball nor volleyball. What is the total number of students in the class?

​​Solution:

Number of students who play basketball, n(B) = 30

Number of students who play volleyball, n(V) = 20

Number of students who play both basketball and volleyball, n(B ∩ V) = 8

Number of students who play neither = 12

n(B ∪ V) = n(B) + n(V) - n(B ∩ V)

= 30 + 20 - 8 = 42

Total students in the class = students who play basketball or volleyball + students who play neither

n(U) = n(B ∪ V) + neither = 42 + 12 = 54

∴ Total 54 students in the class.

প্রশ্ন: একটি কোণকের বক্রতলের ব্যাসার্ধ 7 সে.মি. এবং উচ্চতা 27 সে.মি. হলে কোণকের আয়তন কত?

সমাধান:
দেওয়া আছে,
কোণকের বক্রতলের ব্যাসার্ধ, r = 7 সে.মি.
উচ্চতা, h = 27 সে.মি.

আমরা জানি,
কোণকের আয়তন,
= (1/3)πr2h 
= (1/3) × (22/7) × (7)2 × 27 ঘন সে.মি.
= (22/7) × 49 × 9 ঘন সে.মি.
= 22 × 63 ঘন সে.মি.
= 1386 ঘন সে.মি.