Sunita cuts a sheet of paper into three pieces. Length of first piece is equal to the average of the three single digit odd prime numbers. Length of the second piece is equal to that of the first plus one-third the length of the third. The third piece is as long as the other two pieces together. The length of the original sheet of paper is
- A13
- B15
- C16
- D30Correct
Explanation
Here's a brief explanation:
-
Find L1 (Length of the first piece): The three single-digit odd prime numbers are 3, 5, and 7. Their average = (3 + 5 + 7) / 3 = 15 / 3 = 5. So, L1 = 5.
-
Set up equations for L2 and L3:
- From the third statement: L3 = L1 + L2
- From the second statement: L2 = L1 + (1/3)L3
-
Solve for L2 and L3:
- Substitute L1 = 5 into the equations: L3 = 5 + L2 (Equation 1) L2 = 5 + (1/3)L3 (Equation 2)
- Substitute Equation 2 into Equation 1: L3 = 5 + (5 + (1/3)L3) L3 = 10 + (1/3)L3 L3 - (1/3)L3 = 10 (2/3)L3 = 10 L3 = 10 * (3/2) = 15
- Now find L2 using L2 = 5 + (1/3)L3: L2 = 5 + (1/3)*15 L2 = 5 + 5 = 10
-
Calculate the total length: The lengths of the three pieces are L1 = 5, L2 = 10, and L3 = 15. The length of the original sheet = L1 + L2 + L3 = 5 + 10 + 15 = 30.
Therefore, the length of the original sheet of paper is 30.
The final answer is D.

Related questions
More UPSC Prelims practice from the same subject and topic.
- Prelims 2019CSATQuantitative Aptitude
A and B are two heavy steel blocks. If B is placed on the top of A, the weight increases by 60%. How much weight will reduce with respect to the total weight of A and B, if B is removed from the top o…
- Prelims 2019CSATQuantitative Aptitude
When a runner was crossing the 12 km mark, she was informed that she had completed only 80% of the race. How many kilometres was the runner supposed to run in this event?
- Prelims 2019CSATQuantitative Aptitude
Raju has Rs. 9000 with him and he wants to buy a mobile handset; but he finds that he has only 75% of the amount required to buy the handset. Therefore, he borrows 2000 from a friend. Then
- Prelims 2019CSATQuantitative Aptitude
In 2002, Meenu's age was one-third of the age of Meera, whereas in 2010, Meenu's age was half the age of Meera. What is Meenu's year of birth?
- Prelims 2019CSATQuantitative Aptitude
Rakesh and Rajesh together bought 10 balls and 10 rackets. Rakesh spent 1300 and Rajesh spent 1500. If each racket costs three times a ball does, then what is the price of a racket?
- Prelims 2019CSATQuantitative Aptitude
In an examination, A has scored 20 marks more than B. If B has scored 5% less marks than A, how much has B scored?