CDA Assistant / UDC Islamabad (BS-15/16) Mathematics: Ages MCQs

CDA Assistant / UDC Islamabad (BS-15/16) Mathematics: Ages MCQs — sample questions

1. Question 1

   Q1. If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, then the average marks of all the students is__________?

   • A) 53.33
   • B) 54.68
   • C) 55
   • D) None of these

   Answer: 54.68

   Explanation: The correct value is 54.68. Apply the formula or arithmetic step shown in the question and

2. Question 2

   Q2. A construction project can be completed by 150 workers in 40 days. The project manager brings in 30 more workers after 16 days. In how many days will the remaining work be finished?

   • A) 30 days
   • B) 20 days
   • C) 16 days
   • D) None of these

   Answer: 20 days

   Explanation: The correct value is 20 days. Apply the formula or arithmetic step shown in the question and

3. Question 3

   Q3. A is two years older than B, who is twice as old as C. If the sum of the ages of A, B, and C is 27, how old is B?

   • A) 8 years
   • B) 10 years
   • C) 11 years
   • D) 12 years

   Answer: 10 years

   Explanation: Setting C = x: B = 2x, A = 2x + 2; total = 5x + 2 = 27 → x = 5, so B = 10 years.

4. Question 4

   Q4. The average salary per head of the entire staff of an office including the officers and clerks is Rs.90. The average salary of officers is Rs.600 and that of the clerks is Rs.84. If the number of officers is 2, find the number of clerks in the office?

   • A) 1540
   • B) 960
   • C) 840
   • D) 170

   Answer: 170

   Explanation: Let n = number of clerks; (600×2 + 84n)/(2+n) = 90 → 1200 + 84n = 180 + 90n → n = 170.

5. Question 5

   Q5. If the average of 5, 6, 7, and X is 10, what is the value of 'X'?

   • A) 12
   • B) 22
   • C) 32
   • D) 42

   Answer: 22

   Explanation: (5 + 6 + 7 + X)/4 = 10 → 18 + X = 40 → X = 22.