SCERT AP 7th Class Maths Solutions Pdf Chapter 7 Ratio and Proportion Ex 7.7 Textbook Exercise Questions and Answers.

AP State Syllabus 7th Class Maths Solutions 7th Lesson Ratio and Proportion Ex 7.7

Question 1.
Calculate the simple interest accrued on a sum oR 12600, at the rate of 9% per annum for 2 years.
Given principle = ₹ 12600
Time = 2 years
Rate of Interest = 9% ∴ Simple Interest = ₹ 2268

Question 2.
Calculate the simple interest accrued for 3 years and the total amount on a sum of ₹ 85000, at the rate of 11% per annum.
Given Principle = ₹ 85000
Time = 3 years
Rate of Interest = 11% Simple Interest = ₹ 28,050
Total amount = Principle + Interest
= 85000 + 28050
∴ Total amount = ₹ 1,13,050 Question 3.
In what time will ₹ 45000 amounts to ₹ 63000, If the simple Interest Is calculated 10% per annum?
Method 1:
Given principle = ₹ 45000
Rate of Interest = 10%
Amount = ₹ 63000
Let the time = x years Interest = ₹ 4500 x
Amount = Principle + Interest
= 45000 + 4500x = 63000
= 4500x = 63000 – 45000 = 18000
⇒ x = $$\frac{18000}{4500}$$ = 4
∴ Time = 4 years

Method 2:
Given A = ₹ 63000;
P = ₹ 45000; R = 10%; T=?
So I = A – P = 63000 – 45000 = ₹ 18000

But I = $$\frac{\text { PTR }}{100}$$
⇒ 18000 = $$\frac{45000 \times T \times 10}{100}$$
∴ T = $$\frac{18000 \times 100}{45000 \times 10}$$ = 4 years

Question 4.
On a certain amount at the rate of 12% per annum for time 3 years the toti1 interest becomes ₹ 18000. What is the principal amount?
Given Rate of Interest = 12%
Time.= 3 years
Interest = ₹ 18000
Let Principle = ₹ x ∴ Principle = ₹ 50,000 Question 5.
In what time the simple interest accrued on a sum of?35000 at the rate of 13% per annum becomes?27300? 