Exam Type: Written
Post: Officer (Cash)
Written Exam date: 28 April 2018
Exam Time: 2.30 To 4.30 PM
8.
a) 20 weeks
b) A=37.5 And B=7.5
c) 1% loss
d) 1
e) Table=500Tk Chair=100Tk. Total=600 Tk.
f) x=.5 or, 1/2 And y=3
g) 137 travelers
1. A family has 480 kg of rice for X number of weeks. If they need to use the same amount for 4 more weeks, they need to cut down their weekly assumption of rice by 4 kg. what is the value of X?
ATQ,
x (x+4) = 480
x² + 4x – 480 = 0
(x-20) (x+24) = 0
x = -24 or 20
ans : 20 weeks
2. If cos (A+B) = 1/√2 and Cos (A-B) = √3/2, then what is the value of A & B.
[0∘ < A+B ≤ 90∘ And A > B]
As it given, we get–
Cos 45 = 1/√2 = Cos (A+B)
So, A+B = 45
A = 45 – B –(1)
Again,
Cos 30 = √3/2 = Cos (A-B)
A-B = 30
45-B -B = 30
B = 15/2
So, A = 45 – 15/2 = 75/2
Ans : 75/2 & 15/2
3. A shopkeeper sells two shirt at the same price. He makes one on 10% profit and 10% loss on another. What is the total gain or loss percent?
Let, he sells each shirt at 990 tk
total SP = 990*2 = 1980 tk
First CP = 990/90% = 1100
Second SP = 990/110% = 900
Total CP = 1100+900 = 2000 tk
CP > SP
Loss amount = 2000-1980 = 20 tk
So, Loss Percent = (20/2000) * 100
= 1
Ans : 1% Loss
4.
a ^ (q-r)
= {xy^(p-1)}^(q-r)
= x^ (q-r) * y^ (pq – rp -q +r)
Same as
b^ (r-p) = x^(r-p) * y(qr-pq-r+p)
c^ (p-q) = x^(p-q) * y(rp -qr -p + q)
LHS = x^(q-r+r-p+p-q) * y^ (pq – rp -q + r + qr -pq -r + p + rp – qr -p +q)
= x⁰ * y⁰
= 1 * 1
= 1
= R.H.S. [ Proved ]
5. Price of 3 tables and 5 Chairs is 2000 tk. And price of 5 Tables and 7 Chairs is 3200 tk. Find the price of 1 Table and 1 chair?
=>
Table = T & Chair = C
3T + 5C = 2000
21T + 35C = 14000
35C = 14000-21T —(1)
Again,
5T + 7C = 3200
25T + 35C = 16000
25T + 14000 – 21T = 16000
T = 2000/4 = 500 TK
So,
3*500 + 5C = 2000
C = 500/5 = 100 TK
Price of 1 table & 1 Chair = 500+100 = 600 tk
Ans : 600 tk.
6. Equation solve
Given That,
1/2x + 6/y = 3
12x + y = 6xy
y = 6xy – 12x
5y = 30xy – 60x —(1)
Again, given that–
5/x + 3/y = 11
3x + 5y = 11xy
3x + 30xy – 60x = 11xy
57x = 19xy
y = 3
So,
3 = 6*x*3 – 12x
18x – 12x = 3
x = 3/6 = 1/2
[Proof] ::
At 1st equation –
1/{2 *(1/2)} + 6/3 = 3
1+ 2 = 3
At 2nd equation –
5/(1/2) + 3/3 = 11
10 + 1 = 11
Ans :: (x,y) = (1/2, 3)
7. In a survey at an airport, 55 travelers said that last year they had been to india, 53 said they had been to Nepal, 79 said they had been to Bhutan. 18 had been to india & nepal, 17 had been india & bhutan, 25 had been to nepal & bhutan, 10 had been to all three countries. How many travelers took part in the survey?
Let, Total = T
We know,
All = A+B+C + (All common) – (Two common)
ATQ,
T = 55+53+79 + 10 – (18 +17 +25)
= 197 – 60
= 137
Ans :: 137 Travelers
Detail solution is coming soon……
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