NCTB Class 8 Math Chapter Two Exercise 2.1 Solution by Math Expert. Bangladesh Board Class 8 Math Solution Chapter 2 Profits Exercise 2.1 Solution.
Board |
NCTB |
Class |
8 |
Subject |
Mathematics |
Chapter |
2 |
Chapter Name |
Profits |
Exercise |
2.1 Solution |
Exercise 2.1 Solution
(1) With profit 20% selling price = (100+20)
= 120 Rs.
Let, CP = 100 Rs.
Therefore, Here, SP 120 Rs then CP = 100 Rs.
Therefore, SP 1 Rs. Then CP = 100/120 Rs.
Therefore, 576 Rs. Then CP = 100×576/120
= 480 TK.
Therefore, SP of Retailer = 480 TK.
Now, 20% profit, SP = (100+20)
= 120 TK.
If SP 120 TK Then CP = 100 TK.
Therefore, If SP 120 TK then CP = 100/120 TK.
Therefore, If SP 480 TK then C P = 100×480/120 TK.
= 400 TK.
Therefore, Cost price of whole seller = 400 TK.
(2) Let, cost price = 100 TK.
5% loss, SP = (1000-5)
= 95 Tk.
Therefore, If SP 95 TK; then CP = 100 TK.
Therefore, 1 TK; then CP = 100/95 TK.
Therefore, 2375 TK; then C P = 100×2375/95 TK.
= 2500 TK.
Again, 6% profit, SP = (100+6) = 106 TK.
Therefore, If C P 100 TK, then SP = 106 TK.
Therefore, If CP 2500 TK, then S P = 106×2500/100
= 2650 TK.
Therefore, Selling price = 2650 TK.
(3) Taking L.C.M 10, 15, 12 —–
= 60.
Therefore, 10 bananas, CP = 30 TK.
Therefore, 1 bananas, C P = 30/10 TK.
Therefore, 60 bananas, C P 30 x 60/10 TK.
= 180 TK.
Now, 15 bananas CP = 30 TK.
1 bananas CP = 30/15 TK.
60 bananas C P = 30×60/15
= 120 TK.
Therefore, Total (60+60) 120 bananas cost price = (180+120) TK = 30 TK.
Therefore, 12 bananas SP = 30 TK.
1 bananas SP 30/12 TK.
Therefore, 120 bananas S P = 30×120/12 TK.
= 300 TK.
Therefore, C P = S P = 300 TK.
Therefore, No profit & No loss.
(4) Here, r = 10.50 %
P = 2000 Tk.
n = 5 yr.
∴ Profit = 2000 x 10.50/100 x 5
= 1050 TK.
(6) Here, P = 13000 TK.
I = (18850-13000) TK.
= 5850 TK.
N = 5yr.
R =?
Therefore, We know that,
I = p .r . n/100 (P mean Principal; r means rate percentage and n means number of times)
=> r = I/p . n
= 5850/13000×5
= 9/100
= 9%
(7) Let, P = 100 TK.
8 year later, amount = (100×2) TK.
= 200 TK.
Therefore, Interest = (200-100) = 100 Tk.
Therefore, Here P = 100 TK.
I = 100 TK.
n = 8 year.
R =?
We know, I = p .n .r
=> 100 = 100 x 8 x r
=> r = 100/100×8
= 12.50%
(8) 1^{st}, P = 6500 TK.
n = 4 year
A = 8840 TK.
I = A- P
= (8840-6500) TK.
= 2340 TK.
R =?
We know, I = P n r.
=> 2340 = 6500x 4 x r
=> r = 2340/ 6500×4
= 9%
2^{nd}, A = 10200 TK.
n = 4 year
P =?
And, r = 9%
We know, A = P + I
= P+ P n r
=> 10200 = P (1+n r)
= P (1+ 4 x 9/100)
=> 10200 = P (1 + 9/25)
=> 10200 = P (34/25)
=> P = 25x 10200/34
= 7500 TK.
(9) Here, n = 4 year
I = 4760 TK.
r = 8.50%
p =?
We know, I = p n r
=> 4760 = P x 4 x 8.50/100
=> P = 4760 x 100 x 100/4 x 850
= 14000 TK.
Therefore, Amount deposit in the bank 14000 TK.
(10) Let, P = 100 TK.
In 6 year, Amount = (100×2) = 200 TK.
6 year, Interest = (200-100) = 100 TK.
In 100 TK, 6 year Interest 100 TK.
Therefore, 100 TK, 1 year Interest 100/6 TK.
Therefore, 100 TK, 4 year Interest 100 x 4/6 TK.
= 200/3 TK.
Therefore, Amount = (100+ 200/3) = 500/3 TK.
Therefore, when amount 500/3, P = 100 TK.
Therefore, amount 1, P = 3x 100/500 TK.
Therefore, Amount 2050, P = 3x 100x 2050/500
= 1230 TK.
(11) 1^{st}, r = 6% ; n = 4 year
P = 500 TK; I =?
We know, I = p n r
= 500 x 4 x 6/100
= 120 TK.
2^{nd}, r = 5% ; n = 2 year 6 month
= (2 + 6/12)
= 2 ½ year
Therefore, I = 120 TK;
We know, I = P n r
=> 120 = P x 2.5 x 5/100
=> P = 120 x 100/ 2.5 x 5
= 960 TK.
(12) Rate of interest increase = (100-8) = 2%
Therefore, In 100 TK. 1 year Interest 2 TK.
Therefore 100 TK, 4 year Interest (2 x 4) TK.
= 8 TK.
If, increasing 8 TK, P = 100 TK.
Therefore, increasing 2 TK, P = 100/8 TK.
Therefore, Increasing 128 TK, P = 100x 128/8
= 1600 TK.
(13) Let, principal = P
Therefore, P + 5 year interest = 1830 TK.
P + 3 year Interest = 1578 TK.
(-)________________________________________
2 year interest = 252 TK.
Therefore, 1 year interest = 252/2 TK.
Therefore, 3 year interest = 252x 3/2
= 378 TK.
Principal = Amount – Interest
= (1578-378) TK.
= 1200 TK.
Therefore, 1200 TK, 3 year interest is 378 TK.
Therefore, 1 TK, 1 year interest is 378/1200 x3 Tk.
Therefore, 100 TK, 1 year Interest 378 x100/1200 x 3 TK.
= 10.50 TK.
Therefore, Interest rate 10.50%.
Where is the solution of the rest of the maths???There are 20 maths in 2.1 but u only gave 13….where are the rest of the maths solution???
Rest are coming soon
Sir I want to answar 2.1question no.20 class 8(JSC)
Sir i also want ans. published on google
Please! Sir now i want to ans. Importantly .
When will be the rest published