Finding Time when Principal and Rate are given
In this section you will learn finding time when principal and rate are given in easy way. The time period may be in years, days or in months. For everyone we have different formulas.
When time in years
S.I x 100
Time = T = 
P x R
When time in days
S.I x 100 x 365
Time = T = 
P x R
When time in months
S.I x 100 x 12
Time = T = 
P x R
Examples :
1) Principal = P = $3500, S.I = $700 and rate = R = 5%. Find the time period in years.
Solution :
S.I x 100
Time = T = 
P x R
700 x 100
Time = T = 
3500 x 5
70,000
Time = T = 
17,500
Time = 4 years.
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2) Principal = P = $4800, S.I = $900 and rate = R = 7.5%. Find the time period in months.
Solution :
S.I x 100
Time = T = 
P x R
900 x 100 x 12
Time = T = 
4800 x 7.5
1,080,000
Time = T = 
36000
Time = 30 months.
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3) Principal = P = $7300, S.I = $500 and rate = R = 4%. Find the time period in days.
Solution :
S.I x 100
Time = T = 
P x R
500 x 100 x 365
Time = T = 
7300 x 5
18250000
Time = T = 
36500
Time = 500 days.

Practice
Complete the following table:
Principal (P) 
Rate (R) 
Time(T) 
Simple interest (SI) 
$8000 
6 % 
 
$450 
$5664 
13 ¾ 
 (in month) 
$584.10 
$3125 
15% 
 (in days) 
$93.75 
$500 
7% 
 (in years) 
105 
$250 
8% 
 (in years) 
$80 
Simple Interest (S.I)
• Finding rate when Principal and time are given
• Finding time when Principal and rate are given
• Solved examples on Simple Interest
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