Mathematics — Old Questions (TPSC)
Q41. Four-fifth of a number is greater than three-fourth of that number by 4. the number is :
Let the number be x
Four-fifth of the number = (4 ÷ 5)x
Three-fourth of the number = (3 ÷ 4)x
Given that,
(4 ÷ 5)x is greater than (3 ÷ 4)x by 4
So,
(4 ÷ 5)x − (3 ÷ 4)x = 4
Taking LCM of 5 and 4 = 20
(16x − 15x) ÷ 20 = 4
x ÷ 20 = 4
x = 80
Answer: The number is 80.
📌 Exam tip: Convert fractions to a common denominator first to avoid mistakes.
Q42. The length of a rectangular field is twice its breadth. If the perimeter of the field is 150 metre, find its lenght :
Let breadth of the rectangular field = x metre
Then length of the field = 2x metre
Perimeter of a rectangle = 2(length + breadth)
Given perimeter = 150 metre
So,
2(2x + x) = 150
2(3x) = 150
6x = 150
x = 25
Length of the field = 2x = 2 × 25 = 50 metres
Answer: The length of the field is 50 metres.
📌 Exam tip: Always express length in terms of breadth when a ratio is given.
Q43. Find the square root of 0.000169 :
Q44. Convert a speed of 10 m/s into km/h :
Q45. 96 % of the cost of a TV is Rs. 10,464.00. What is its total cost ?
Q46. If (3a + 7b) : (5a - 3b) = 5:3, a:b will be :
Q47. A sum of money at simple interest doubles itself in 10 years. Find the rate of interest per annum.
Q48. A alone can finish a piece of work in 12 days and B alone can do it in 15 days. How much time will they take to finish this work if they work together ?
Q49. A man bought an article for Rs. 850.00 and sold it at a gain of 8 %. For how much did he sell it ?
Q50. If the diameter of a circle is 14 cm, what is the value of its circumference ?