ML Aggarwal Solution Class 10 Chapter 2 Banking Exercise 2
Exercise 2
Question 1
Shweta deposits Rs. 350 per month in a recurring deposit account for one year at the rate of 8% p.a. Find the amount she will receive at the time of maturity.
Sol :
Deposit per month = Rs 350,
Rate of interest = 8% p.a.
Period (x) = 1 year
= 12 months
∴Total principal for one month $350 \times \frac{x(x+1)}{2}=\operatorname{Rs} 350 \times \frac{12 \times 13}{2}$
= Rs. 350×78
= Rs. 27300
∴Interest $=\frac{PRT}{100}=\frac{27300 \times 8 \times 1}{100 \times 12}=$ Rs. 182
∴Amount of Maturity=Rs 350×12+Rs 182
=Rs 4200+182=Rs 4382
Question 2
Salom deposited Rs 150 per month in a bank for 8 months under the Recurring Deposit Scheme. ‘What will be the maturity value of his deposit if the rate of interest is 8% per annum ?
Sol :
Deposit per month = Rs. 150
Rate of interest = 8% per
Period (x) = 8 month
∴Total principal for one month$=\operatorname{Rs.} 150 \times \frac{x(x+1)}{2}=\operatorname{Rs} 150 \times \frac{8(8+1)}{2}$ $=\frac{150 \times 8 \times 9}{2}=\operatorname{Rs} .5400 .$
∴Interest $=\frac{p r t}{100}=\frac{5400 \times 8 \times 1}{100 \times 12}=$ Rs. 36
∴Amount of Maturity=Rs 150×8+Rs 36
=Rs 1200+36=Rs 1236
Question 3
Mrs. Goswami deposits Rs. 1000 every month in a recurring deposit account for 3 years at 8% interest per annum. Find the matured value. (2009)
Sol :
Deposit per month (P) = Rs. 1000
Period = 3 years = 36 months
Rate = 8%
Total principal $=\frac{36(36+1)}{2} \times 1000$
Intercst $=\frac{\mathrm{PR} \mathrm{T}}{100}=\frac{36 \times 37 \times 1000 \times 8}{ 2 \times 12 \times 100}$
=12×37×10=4440
Matured value $=P \times n+S . I=1000 \times 36+4440=36000+4440=$ Rs. 40440
Question 4
Kiran deposited Rs. 200 per month for 36 months in a bank’s recurring deposit account. If the banks pays interest at the rate of 11% per annum, find the amount she gets on maturity ?
Sol :
Amount deposited month (P) = Rs. 200
Period (n) = 36 months,
Rate (R) = 11% p.a.
Now amount deposited in 36 months = Rs. 200 x 36 = Rs 7200
$=200\left(\frac{36(36+1)}{2}\right) \times \frac{1}{12} \times \frac{11}{100}$
$=\frac{200 \times 36 \times 37 \times 11}{2 \times 12 \times 100}=1221$
∴Kiran will get maturity value=7200+1210=8421
Question 5
Haneef has a cumulative bank account and deposits Rs. 600 per month for a period of 4 years. If he gets Rs. 5880 as interest at the time of maturity, find the rate of interest.
Sol :
Interest = Rs. 58800
Monthly deposit (P) = Rs. 600
Period (n)=4 years or 48 months
∴Deposit for 1 month $=\frac{P(n)(n+1)}{2}$
$=\frac{600 \times 48 \times 49}{2}=\mathrm{Rs} .705600$
Let, rate of interest =r % p.a.
Interest $=\frac{\operatorname{PRT}}{100}$
$5880=\frac{705600 \times r \times 1}{100 \times 12}$
5880=588r
∴$r=\frac{5880}{588}=10$
∴Rate of interest =10 % p.a.
Question 6
David opened a Recurring Deposit Account in a bank and deposited Rs. 300 per month for two years. If he received Rs. 7725 at the time of maturity, find the rate of interest per annum. (2008)
Sol :
Deposit during one month (P) = Rs. 300
Period = 2 years = 24 months.
Maturity value = Rs. 7725
Now principal for 1 month $=\frac{P \times n(n+1)}{2}$
$=\frac{300 \times 24(24+1)}{2}=\frac{300 \times 24 \times 25}{2}=$ Rs. 90000
∴Interest earned $=\frac{\mathrm{PRT}}{100}=\frac{90000 \times \mathrm{R} \times 1}{100 \times 12}$
=75R
Now 300×24+75R=7725
7200+75 R=7725
75 R=7725-7200=525
$\mathrm{R}=\frac{525}{75}=7$
∴Rate of Interest =7 % p.a.
Question 7
Mr. Gupta-opened a recurring deposit account in a bank. He deposited Rs. 2500 per month for two years. At the time of maturity he got Rs. 67500. Find :
(i) the total interest earned by Mr. Gupta.
(ii) the rate of interest per annum.
Sol :
Deposit per month = Rs. 2500
Period = 2 years = 24 months
Maturity value = Rs. 67500
∴Total principal for 1 month $=\frac{\mathrm{P} \times n(n+1)}{2}$
$=₹ \frac{2500 \times 24 \times 25}{2}=₹ 750000$
∴Interest =₹ 67500-24×2500
=₹ 67500-60000=₹ 7500
Period $=1$ month $=\frac{1}{12}$ year
∴Rate of interest $=\frac{\mathrm{S.I.} \times 100}{\mathrm{P} \times \mathrm{T}}=\frac{7500 \times 100 \times 12}{750000 \times 1}$
=12%
Question 8
Shahrukh opened a Recurring Deposit Account in a bank and deposited Rs 800 per month for $1 \frac{1}{2}$ yeas . If he received Rs 15084 at the time of maturity, find the rate of interest per annum.
Sol :
Money deposited by Shahrukh per month (P)= Rs 800
r = ?
No. of months $(n)=1 \frac{1}{2}=\frac{3}{2} \times 12$
=18 months
∴Interest $=\mathrm{P} \times \frac{n(n+1)}{2 \times 12} \times \frac{r}{100}$
$=₹ 800 \times \frac{18(18+1)}{2 \times 12} \times \frac{r}{100}$
$=₹ 800 \times \frac{18 \times 19}{2 \times 12} \times \frac{r}{100}=114 r$
∴Maturity amount =114 r+800×18
₹ 15084=114 r+₹ 14400
₹ 15084-₹ 14400=114 r
684=114 r
$r=\frac{684}{114}=6 \%$
Question 9
Mohan has a recurring deposit account in a bank for 2 years at 6% p.a. simple interest. If he gets Rs 1200 as interest at the time of maturity, find:
(i) the monthly instalment
(ii) the amount of maturity. (2016)
Sol :
Interest = Rs 1200
Period (n) = 2 years = 24 months
Rate (r) = 6% p.a.
Let monthly deposit =₹ P p.m.
∴Interest $=\frac{\mathrm{P} \times n(n+1)}{2 \times 12} \times \frac{r}{100}$
$1200=\frac{P \times 24 \times 25}{24} \times \frac{6}{100}$
$1200=\frac{6}{4} \mathrm{P}$
∴$P=\frac{1200 \times 4}{6}=800$
∴Monthly deposit =₹ 800
and maturity value =P × n+ Interest
$=₹ 800 \times 24+₹ 1200$
$=₹ 19200+₹ 1200=₹ 20400$
Question 10
Mr. R.K. Nair gets Rs 6,455 at the end of one year at the rate of 14% per annum in a recurring deposit account. Find the monthly instalment.
Sol :
Let monthly instalment is Rs P
here n = 1 year = 12 months
n = 12
₹ 645500=1291 P
$P=\frac{645500}{1291}=₹ 500$
Question 11
Samita has a recurring deposit account in a bank of Rs 2000 per month at the rate of 10% p.a. If she gets Rs 83100 at the time of maturity. Find the total time for which the account was held.
Sol :
Deposit per month = Rs 2000,
Rate of interest = 10%, Let period = n months
Then principal for one month
$=2000 \times \frac{n(n+1)}{2}=1000 n(n+1)$ and interest
$=\frac{1000 n(n+1) \times 10 \times 1}{100 \times 12}=\frac{100 n(n+1)}{12}$
∴$=2000 \times n+\frac{100 n(n+1)}{12}$
⇒24000 n+100n2+100 n=83100 \times 12
⇒240 n+n2+n=831 \times 12
⇒n2+241 n-9972=0
⇒n2+277 n-36 n-9972=0
⇒n(n+277)-36(n+277)=0
⇒(n+277)(n-36)=0
Either n+277=0, then n=-277, which is not possible.
or n-36=0, then x=36
∴Period=36 months or 3 years
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