বিসিএস, ব্যাংক, প্রাথমিক শিক্ষক ও সকল সরকারি চাকরির বিগত সালের প্রশ্ন ও অধ্যায়ভিত্তিক নির্ভুল সমাধান
Solution:
Cost of first variety = 250 Taka/kg
Cost of second variety = 350 Taka/kg
Ratio = 3:2
Cost price of mixture = {(3×250) +(2×350)}/(3+2)
= 1450/5
= 290 Taka/kg
Profit = Selling price - Cost price
= 360 - 290
= 70 Taka/kg
Profit percentage = (70/290) × 100%
= 24.13%
= 25%
Solution:
Let,
The price of an article is 100 Tk.
If the price increased by 25%,
So, the new price will be after increase = 100 + {100 × (25/100)} Tk.
= 100 + 25 Tk.
= 125 Tk.
Then the new price decreased by 20%,
So, the new price will be after decrease = 125 - {125 × (20/100)} Tk.
= 125 - 25 Tk.
= 100 Tk.
∴ The net effect on the price of the article is = (100 - 100)
= 0 Taka
So, after both the increase and the decrease, the price remains the same.
Solution:
The cost price of each gem is 20 per Tk. = Tk. 1/20
The price of each gem is 30 per Tk. = Tk. 1/30
∴ Average cost of gem = {(1/20) + (1/30)}/2
= (3 + 2)/(2 × 60)
= 5/120
= 1/24
The selling price of mixed gem = Tk. 1/25
∴ Loss = (1/24) - (1/25) = 1/600
Cost price 1/24 then loss Tk. 1/600
Cost price 1 then loss Tk. (1/600)/(1/24)
∴ Cost price 1 then loss Tk. {(1/600)/(1/24)} × 100 = 4%
∴ There is a loss of 4%
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
