Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
88 views
in Aptitude by (115k points)
closed by
A sum of Rs. 10 is lend to be returned in 11 monthly instalments of Rs. 1 each, interest being simple. The rate of interest charged is:
1. \(9 \frac{1}{11} \%\)
2. 10%
3. \(21 \frac{9}{11} \%\)
4. 22%

1 Answer

0 votes
by (114k points)
selected by
 
Best answer
Correct Answer - Option 3 : \(21 \frac{9}{11} \%\)

Given :

A sum of Rs. 10 is lend to be returned in 11 monthly instalments of Rs . 1 each interest being simple 

Formula used :

Simple interest = P × R× T /100 

Principal(P), Rate(R) and Time(T)

Calculation :

Let the rate of interest be R% per annum

⇒ Amount to be paid (if paid at the end of 11 months)

⇒ 10 + [10 × R × (11/12) / 100] = 10 + (11R/120)

⇒ Total effective payment = (Rs. 1 + interest on Rs. 1 for 10 months) + (Rs. 1 + interest on Rs. 1 for 9 months) + .... +(Rs. 1 + interest on Rs. 1 for 1 months) + Rs. 1

⇒ (1 + 1 × R × (10/12) / 100)   + (1 + 1 × R × (9/12) / 100) + .... + (1 + 1 × R × (1/12) / 100) + 1

⇒ (1 + 10R/1200) + (1 + 9R/1200) + .... + (1 + R/1200) + 1

⇒ 11 + R(1 + 2 + .... + 10)/1200

⇒ 11 + R(10 × 11 / 2)/1200

⇒ 11 + R(10 × 11 / 2)/1200

⇒ 11 + 11R/240 

Now we have, 

⇒ 10 + 11R/120 = 11 + 11R/240

⇒ 11R/240 = 1

⇒ R = 240/11 = 21× 9/11%

∴ Rate of interest is 21(9/11)%

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...