বিগত সালের প্রশ্ন ও প্রশ্ন ব্যাংক
বিসিএস, ব্যাংক, প্রাথমিক শিক্ষক ও সকল সরকারি চাকরির বিগত সালের প্রশ্ন ও অধ্যায়ভিত্তিক নির্ভুল সমাধান
Solution:
Let the number of student and teacher be represented by S and T respectively.
S : T = 30 : 1
S/T = 30/1
S = 30T.............(1)
If number of students increases by 50 and number of teachers increases by 5
50 + S : T + 5 = 25 : 1
⇒ (50 + S)/(T + 5) = 25/1
⇒ S + 50 = 25(T + 5)
⇒ S + 50 = 25T + 125
⇒ 30T + 50 = 25T + 125 [From (1)]
⇒ 30T - 25T = 125 - 50
⇒ 5T = 75
⇒ T= 75/5 =15
∴ No of teachers=T=15
Solution:
Let the monthly income of one person be 4x and that of the other be 5x
Let the monthly expenses of one person be 7y and that of other be 9y
According to the question,
4x - 7y= 50...................(1)
5x - 9y= 50....................(2)
(1) × 9 - (2) × 7
36x - 63y - 35x + 63y = 450 - 350
x = 100
Monthly income of one person
= 4 ×100 = 400
Monthly income of the other person
= 5 × 100 = 500
Solution:
Let
2A = 3B = 4C = x
2A = x
A = x/2
3B =x
B = x/3
4C = x
C = x/4
A : B : C = x/2 : x/3 : x/4
= (x/2) × 12 : (x/3) × 12 : (x/4) × 12
= 6 : 4 : 3
Solution:
Let the total profit be Tk. 100.
After paying to charity, A's share = (95 × 3/5) = 57
If A's share is Tk. 57, total profit = 100.
If A's share is Tk. 855, total profit = (100/57) × 855 = 1500.
Solution:
Ratio of Reena and Shaloo shares = (35000 × 8) : (42000 × 10)
= 280000 : 420000
= 2 : 3.
Reena's share Tk. 31570 × (2/5)
= Tk. 12628
এখানে,
15% of A = 20% of B
বা, A × 15/100 = B × 20/100
বা, A × 15 = B × 20
বা, A/B = 20/15
বা, A/B = 4/3
A : B = 4 : 3
Solution: a : b = 4 : 7 = 20 : 35
b : c = 5 : 6 = 35 : 42
a : b : c = 20 : 35 : 42