CTET Maths - Algebra
- Option : B
- Explanation : Since, the sum becomes three times in 8 yr. ∴3P - P = (P x R x 8)/100 =>2 = 8R/100. R= 200/8 = 25%. Again, in 12 yr let sum becomes n times, then nP - P = (P x 25 x 12)/100 . => n-l=3 => n=4 times
at 10% per annum,
compounded yearly.
34. The difference between CI and SI on 8000 Rs for 2 yr is 20 Rs. Find the rate of interest.
- Option : A
- Explanation : Here, P = 8000 Rs, x = 20 Rs.
p= x(100/r)2
⇒8000 = 20(100/r)2
400 = 1002 /r2 .
r2 = (100 x 100)/400 = 25.
r = 5% per annum
- Option : C
- Explanation : Let purchase price be x Rs.
Price after 1 year,
x-(10/100) × x=9x/10.
Price after II year,
(9x/10) - (10/100) × (9x/10) =81x/100.
According to the question,
81x/100 = 24300.
x=(24300 × 100)/81
x= 30000 Rs
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