বিগত সালের প্রশ্ন ও প্রশ্ন ব্যাংক
বিসিএস, ব্যাংক, প্রাথমিক শিক্ষক ও সকল সরকারি চাকরির বিগত সালের প্রশ্ন ও অধ্যায়ভিত্তিক নির্ভুল সমাধান
Given:
- Total money lent = Tk. 10,000
- Tk. 2,000 at 8%
- Tk. 4,000 at 7.5%
- Tk. 1,400 at 8.5%
- Average interest = 8.13%
Step 1: Remaining amount
Remaining = 10,000 - (2,000 + 4,000 + 1,400) = Tk. 2,600
Step 2: Interest from first three parts
- 2000 × 8% = 160
- 4000 × 7.5% = 300
- 1400 × 8.5% = 119
Total known interest = 160 + 300 + 119 = Tk. 579
Step 3: Total required interest (average 8.13%)
Total interest = 10000 × 8.13% = Tk. 813
So, interest needed from remaining = 813 - 579 = Tk. 234
Step 4: Find rate on remaining Tk. 2,600
(2600 × r) / 100 = 234
⇒ 26r = 234
⇒ r = 234 / 26 = 9%
∴ Required rate of interest = 9%
Solution:
Here,
P = M
r = M%
I = M
n = 4
We know that,
I = Pnr
M = M × 4 × (M/100)
⇒ 1 = M/25
∴ M = 25
Given:
- Principal (P) = Tk. 6000
- Amount after 4 years = Tk. 7200
- Time = 4 years
Step 1: Calculate Simple Interest (S.I.)
S.I. = 7200 - 6000 = Tk. 1200
Step 2: Use S.I. formula to find the rate:
S.I. = (P × R × T) / 100
1200 = (6000 × R × 4) / 100
⇒ 1200 = 240R
⇒ R = 1200 / 240 = 5%
Step 3: New rate = 1.5 × 5% = 7.5%
Step 4: Calculate new amount for 5 years at 7.5%
S.I. = (6000 × 7.5 × 5) / 100 = 2250
Amount = 6000 + 2250 = Tk. 8250
∴ Final Answer: Tk. 8250
প্রদত্ত:
- মেয়াদ (n) = ১২০ দিন = ৪ মাস = ১/৩ বছর
- মুনাফা (I) = ৩৬০ টাকা
- সুদের হার (r) = ৬% = ৩/৫০
আমরা জানি:
I = P × n × r
⇒ P = I / (n × r)
= ৩৬০ / {(১/৩) × (৩/৫০)}
= ৩৬০ / (১/৫০)
= ৩৬০ × ৫০
= ১৮,০০০ টাকা
∴ তিনি ঋণ নিয়েছিলেন: Tk. ১৮,০০০
Given:
- Rate of interest (r) = 4.5% per annum
- Difference in S.I. between 6 and 4 years = Tk. 216
Let the principal = Tk. P
Simple Interest formula:
S.I. = (P × R × T) / 100
Difference in S.I.:
S.I. for 6 years − S.I. for 4 years = 216
⇒ P × 4.5 × (6 − 4) / 100 = 216
⇒ (9P) / 100 = 216
⇒ P = (216 × 100) / 9 = 2400
∴ The sum is: Tk. 2,400
Given:
- Principal (P) = Tk. 800
- Rate (r) = 9/2 %
- Time (n) = 3 years
Step 1: Calculate Simple Interest (S.I.)
S.I. = (P × r × n) / 100
S.I. = (800 × 9 × 3) / (2 × 100)
S.I. = 21,600 / 200 = Tk. 108
Step 2: Find time when:
- Principal = Tk. 150
- Rate = 8%
- Simple Interest = Tk. 108
We know, I = P × r × n / 100
⇒ n = I / (P × r / 100)
⇒ n = (100 × 108) / (150 × 8)
⇒ n = 10,800 / 1,200 = 9 years
Answer: 9 years