Question

In what time will Rs. 1860 amount to Rs. 2641.20 at simple interest 12% per annum?
A) 2.9 years
B) 3.5 years
C) 4.2 years
D) 4.7 years

Answer 1

Option "B" is the right answer.

S.I. = p×t×r/100

so 1st let's try option "a" put this at the place of time.
so,

S.I. = 1860×12×2.9/100

Interest = 647.28
Amount = Principle+ internet
1860+647.28 = 2507.28 (Wrong Answer)
So again do the same thing with option "B"

S.I. = 1860×12×3.5/100

Interest = 781.20
Amount = 1860+781.20 = 2641.20

So option "B" is right answer.
You can do this very quickly by using calculator in MCQ question if calculator is allowed.


Hope this'll help you..

Answer 2

Answer:   B) 3.5 years 

Explanation:

Given that Rs. 1860 will become Rs. 2641.20 at 12%

=> Simple Interest = 2641.20 - 1860 = Rs. 781.20

We know I = PTR/100

=> 781.20 x 100 = 1860 x T x 12

=> T = 78120/1860x12

=> T = 78120/22320

=> T = 3.5 years.