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Numerical Ability
Simple & Compound Interest
If a sum of money compound annually amounts of thrice itself in 3 years. In how many years will it become 9 times itself.
(a) 6 (b) 8 (c) 10 (d) 12
Read Solution (Total 5)
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- let the amount be A
for 3 years it becomes 3A
so, for 6 years it becomes 3(3A)=9A
hence the answer is option a)6 - 13 years agoHelpfull: Yes(36) No(13)
- ci=p(1+r/100)^t
given
3p=p(1+r/100)^3
now (1+r/100)^3=3
now squaring on both sides
(1+r/100)^3*2=3^2
(1+r/100)^6=9
hence answer is 6 years - 10 years agoHelpfull: Yes(12) No(1)
- let, initial amount be 100 rs
it get triples in 3 years ie. we are getting 300 rs in 3 years
so intrest is 300-100=200 Rs
now when it become 9 times we will get intrest =900-100=800Rs
We get,
3 YEARS==200
? YEARS==800
?=(800*3)/200=12 YEARS
AND THIS IS 100 % CORRECT SOLUTION - 10 years agoHelpfull: Yes(1) No(15)
- bbrihvihivhihhi
- 10 years agoHelpfull: Yes(0) No(13)
- let principle=x in 3 years it became 3x
3x=x(1+(r/100))^3==> 3=(1+(r/100))^3------------------> I
9x=x(1+(r/100))^n
9=(1+(r/100))^n write 9= 3^2
==> 3^2=(1+(r/100))^n sub equ I here
((1+(r/100))^3)^2=(1+(r/100))^n
1+(r/100))^6=(1+(r/100))^n
so n=6. - 8 years agoHelpfull: Yes(0) No(0)
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