বিগত সালের প্রশ্ন ও প্রশ্ন ব্যাংক
বিসিএস, ব্যাংক, প্রাথমিক শিক্ষক ও সকল সরকারি চাকরির বিগত সালের প্রশ্ন ও অধ্যায়ভিত্তিক নির্ভুল সমাধান
Solution:
Good at Mathematics n(M) = 65
Good at Statistics n(S) = 45
good in both Mathematics and Statistics n(M ∩ S)
We know that
n(M ∪ S) = n(M) + n(S) - n(M ∩ S)
⇒ n(M ∩ S) = n(M) + n(S) - n(M ∪ S)
= 65 + 45 - 100 = 110 - 100 = 10
Solution:
Required Percentage = (0.57 ×100)/3.8
= (57 × 100 × 10)/(38 × 100)
= 15%
Solution:
Let, A's salary x and B's salary = (3000 - x)
ATQ,
⇒ (100 - 95)% of A = (100 - 85)% of B
⇒ (5/100)x = (15/100)(3000 - x)
⇒ x = 3(3000 - x)
⇒ x = 9000 - 3x
⇒ 4x = 9000
⇒ x = 9000/4
⇒ x = 2250
So, A's salary is Tk. 2250
Solution:
To obtain Tk. 12, investment = Tk. 96
To obtain Tk. 800, investment = Tk. (96/12) × 800 = Tk. 6400
Solution:
Profit for first Tk. 1000 = 1000(5/100)
= Tk. 50
Total sales excess of Tk. 1000 = (12000 - 1000)
= Tk. 11000
∴ Profit for excess of Tk. 1000 = 11000(4/100)
= Tk. 440
∴ Total Profit = (50 + 440) = Tk. 490
Solution:
After 3 days, food having for = (30 - 3) = 27 days
After arriving 300 men, total men = (600 + 300) = 900 men
600 men can eat the food for 27 days
∴ 1 man can eat the food for (27 × 600) days
∴ 900 men can eat the food for (27 × 600)/900 days = 18 days
Solution:
Whole work is done by A in (3 × 4) = 12 days
∴ A's 1 day's work = 1/12 part
Whole work is done by B in (4 × 9) = 36 days
∴ B's 1 day's work = 1/36 part
A's 1 day's work : B's 1 day's work
= A's wages : B's wages
= 1/12 : 1/36
= 3 : 1
∴ A's share = (800 × 3/4) Tk = 600 Tk