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What sum of money will yield 900 as simple interest in 3 years at 6% per annum?
5000
4500
6000
5500
5000
Calculate the total percentage interest (R├ЧT=6%├Ч3=18%) and equate 18% to 900. Since 18├Ч5=90, then 18├Ч500=9000, so 1% = 50 and 100% = 5000.
Simple Interest (SI) = 900, Time (T) = 3 years, Rate of Interest (R) = 6% per annum.
P=R├ЧTSI├Ч100тАЛ
Calculate the total percentage interest (R├ЧT=6%├Ч3=18%) and equate 18% to 900. Since 18├Ч5=90, then 18├Ч500=9000, so 1% = 50 and 100% = 5000.
Confusing the simple interest formula with the compound interest formula by trying to apply A=P(1+100RтАЛ)n.
Identify given variables
We are given SI=900, T=3 years, and R=6%.
SI=900,T=3,R=6
State the formula
The standard simple interest formula is SI=100P├ЧR├ЧTтАЛ. Rearranging to find the principal P:
P=R├ЧTSI├Ч100тАЛ
Substitute and solve
Substitute the values into the rearranged formula: P=6├Ч3900├Ч100тАЛ. Calculating the denominator: 6├Ч3=18. Dividing 900 by 18 gives 50, then multiplying by 100 results in 5000.
P=18900├Ч100тАЛ=50├Ч100=5000
A is correct because the principal amount required to earn 900 as simple interest at 6% over 3 years is exactly 5000.
This concept is fundamental for Profit and Loss and Time, Speed, and Distance problems, where interest is analogous to distance and the rate/time relationship acts similarly to speed/time.