RRB NTPC Arithmetic and Number Systems

Question 1

A train 150 m long passes a pole in 15 seconds. What is the speed of the train in km/h?

Accepted Answer

36 km/h

Answer

Speed = Distance/Time = 150/15 = 10 m/s. Converting to km/h: 10 × 18/5 = 36 km/h.

Question 2

The LCM of 12, 18, and 24 is:

Accepted Answer

72

Answer

LCM of 12, 18, 24: Prime factorize: 12=2²×3, 18=2×3², 24=2³×3. LCM = 2³×3² = 8×9 = 72.

Question 3

If the simple interest on a sum for 2 years at 5% per annum is Rs. 400, what is the principal?

Accepted Answer

Rs. 4000

Answer

SI = PRT/100 → 400 = P×5×2/100 → P = 400×100/10 = Rs. 4000.

Question 4

What is 15% of 480?

Accepted Answer

72

Answer

15% of 480 = (15/100) × 480 = 15 × 4.8 = 72.

Question 5

A number when divided by 6 leaves a remainder of 3. What will be the remainder when the same number is divided by 3?

Accepted Answer

0

Answer

If N = 6q + 3, then N = 3(2q+1), so N is exactly divisible by 3, leaving remainder 0.

RRB NTPC Practice Test