বিগত সালের প্রশ্ন ও প্রশ্ন ব্যাংক
বিসিএস, ব্যাংক, প্রাথমিক শিক্ষক ও সকল সরকারি চাকরির বিগত সালের প্রশ্ন ও অধ্যায়ভিত্তিক নির্ভুল সমাধান
Solution:
Since the ratio of foreign : local is 3 : 7,
let's use a total of 10 parts
So if we have a total of 100 students, that means
Foreign students = 30 students
Local students = 70 students
Foreign female students = (1/4) × 30 = 15/2 students
Local female students = (3/4) × 70 = 105/2 students
Total female students = (15/2) + (105/2)
= (15 + 105)/2
= 60 students or 60% of the combined students are female.
Solution:
5% of A + 4% of B = (2/3) (6% of A + 8% of B)
⇒ A/20 + B/25 = A/25 + 4B/75
⇒ (A/20) - (A/25) = (4B/75) - (B/25)
⇒ A/100 = B/75
⇒ A/B = 100/75 = 4/3
∴ A : B = 4 : 3
Solution:
In your wallet, there are Tk 500, Tk 200 and Tk 100. notes in the ratio 5 : 9 : 4
Let,
Number of Tk. 500 note is 5x
Number of Tk. 200 note is 9x
Number of Tk. 100 note is 4x
ATQ,
500 × 5x + 200 × 9x + 100 × 4x = 18800
⇒ 2500x + 1800x + 400x = 18800
⇒ 4700x = 18800
⇒ x = 18800/4700
∴ x = 4
Number of Tk. 500 note is 5x = 5 × 4 = 20
Number of Tk. 200 note is 9x = 9 × 4 = 36
Number of Tk. 100 note is 4x = 4 × 4 = 16
Solution:
Let,
g = number of girls,
b = number of boys
∴ Total number of students = b + g
ATQ,
g/4 = (b + g)/6
⇒ 6g = 4b + 4g
⇒ 2g = 4b
⇒ 2/4 = b/g
⇒ b/g = 1/2
∴ b : g = 1 : 2
Solution:
Let,
the salaries of A and B last year be Tk. 3x and Tk. 4x respectively.
Then,
A's present salary = Tk. (5/4) × 3x
= Tk. 15x/4
B's present salary = Tk.(3/2) × 4x
= Tk. 6x.
According to the question,
(15x/4) + 6x = 4160
⇒ 15x + 24x = 4160 × 4
⇒ 39x = 4160 × 4
⇒ x = (4160 × 4)/39
So, A's present salary = Tk. (15/4) × {(4160 × 4)/39}
= Tk.1600