Multiple choice

What is the principal sum? P : The sum amounts to Rs. $690$ in $3$ yrs at Simple Interest. Q : The sum amounts to Rs. $750$ in $5$ yrs at Simple interest. R : The rate of interest is $5\%$ per annum.

  1. P & Q will give the answer

  2. R & Q will give the answer

  3. P & R will give the answer

  4. Any two will give the answer
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Simple interest I = P * R * T / 100. P and Q provide two equations with two variables (P and R), allowing us to solve for P. R and Q provide two equations with two variables (P and T), allowing us to solve for P. P and R provide one equation with two variables (P and T), but R is known, so we can solve for P. Thus, any two statements are sufficient.

AI explanation

Statements P and Q are sufficient because the difference in amounts, which is Rs. 60, represents the interest for 2 years, allowing you to find the yearly interest and thus the principal. Statements Q and R are sufficient because you can use the final amount formula, Principal plus (Principal times 5 times 0.05), to solve for the principal of Rs. 600. Finally, statements P and R are also sufficient because the formula becomes Principal plus (Principal times 3 times 0.05) equals Rs. 690, which solves to a principal of Rs. 600; therefore, any two of the statements will give the answer.

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