# Collins Maths Solutions Class 7 Chapter 9

## Collins Maths Solutions Class 7 Chapter 9 Simple Interest

Welcome to NCTB Solution. Here with this post we are going to help 7th class students for the Solutions of Collins Maths Class 7 Mathematics, Chapter 9, Simple Interest. Here students can easily find chapter 7 solutions with exercise wise explanation. Students will find proper solutions for Exercise 9.1 Our teacher’s solved every problem with easily understandable methods so that every students can understand easily. Here in this post all the solutions are based on ICSE latest Syllabus.

Simple Interest Exercise 9.1 Solution :

Question no – (1)

Solution :

(a) Principal = Rs 480

Rate of interest = 5 1/4%

Time = 1 1/4 years

Simple interest,

= 480 × 21 × 5/4 × 4 × 100

= 31.5 Rs

Thus, the simple interest will be 31.5 Rs.

(b) Principal = Rs 2224

Rate of interest = 6.25%

Time = 2 years 3 month = (12 + 3) m =  15 month.

Simple interest,

= (2224 × 6.25/100 × 2 × 3/12)

= (278 + 354.75

= 312.75 Rs.

Hence, the simple interest will be Rs 312.75

Question no – (2)

Solution :

(a) Interest = Rs 455

Rate of interest = 2 1/3%

Time = 3 years

Simple interest,

= P × 7/3 × 3/100

= 455 = 21P/300

= 21P = 455 × 300

= P = 455 × 300/21

= P = 6500 Rs.

So, the amount of borrowed sum will be 6500 Rs.

(b) Interest = Rs 675,

Rate if interest = 12 %

Time = 36 month

Simple interest = P × 12 × 3/100

= 675 =  P × 36/100

= P = 100 × 675/36

= 1875 Rs.

Therefore, the amount of borrowed sum will be 1875 Rs.

Question no – (3)

Solution :

(a) Principal =  RS 1000

Interest = Rs 210

Time = 3 1/2 year.

Simple interest = 1000 × R × 7/2 × 100

=  210 = 1000 × 7R/2 × 100

=  R = 2 × 100 × 210/1000 × 7

= R = 6%

Therefore, rate of interest will be 6%.

(b) Principal = Rs 30,000

Interest = Rs 2310

Time = 2.2 years

Simple interest,

= 2310 =  30,000 × R × 2.2/100

= R = 2310 × 100/30,000 × 2.2

= 3.5%

Hence, the rate of interest will be 3.5%.

Question no – (4)

Solution :

(a) Principal = Rs 1800

Rate =  10% p.a.,

Interest = Rs 420

420 = 1800 × 10 × t/100

= 1800 × 10 × t =  420 × 100

=  t = 420 × 100/1800 × 10

=  2.33

= 2 1/3 years.

So, the required time period will be 2 1/3 years.

(b) Principal = 1080

Rate = 3 1/3% p.a.,

Interest = Rs 90

90 = 1080 × 10 × t/3 × 100

= t = 3 × 100 × 90/1080 × 10

=  2.5 years.

Thus, the required time period will be 2.5 years.

Question no – (5)

Solution :

Amount = P (1 + RT/100)

= 92400 = P (1 + 15 × 2/100)

= P (1 + 30/100)

= P × 13/10

= P = 92400 × 10/13

= P = 71, 077 Rs

Therefore, the borrowed sum will be 71,077 Rs.

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Updated: June 15, 2023 — 8:41 am