Number system short tricks – Career Education Book

There are three traffic signals. Each signal changes colour from green to red and then from red to green. The first signal takes 25 seconds, the second signal takes 39 seconds and the third signal takes 60 seconds to change the colour from green to red. The durations for green and red colours are same. At 2:00 p.m, they together turn green. At what time will they change to green next, simultaneously ?

By admin March 10, 2025

(UPSC CSAT - 2023) 4:00 p.m. 4:10 p.m. 4:20 p.m. 4:30 p.m. Solution: Ans.(2) Time…

Let pp, qq and rr be 2-digit numbers where p < q < r. If pp + qq + rr = tt0, where tt0 is a 3-digit number ending with zero, consider the following statements:

By admin March 10, 2025

1. The number of possible values of p is 5. 2. The number of possible…

How many natural numbers are there which give a remainder of 31 when 1186 is divided by these natural numbers ?

By admin March 10, 2025

(UPSC CSAT - 2023) 6 7 8 9 Solution: Ans.(4) All the factors of 1155…

AB and CD are 2-digit numbers. Multiplying AB with CD results in a 3-digit number DEF. Adding DEF to another 3-digit number GHI results in 975. Further A, B, C, D, E, F, G, H, I are distinct digits. If E = 0, F = 8 then what is A + B + C equal to ?

By admin March 10, 2025

(UPSC CSAT - 2023) 6 7 8 9 Solution: Ans.(1) So D & G should…

D is a 3-digit number such that the ratio of the number to the sum of its digits is least. What is the difference between the digit at the hundred’s place and the digit at the unit’s place of D?

By admin February 20, 2025

(UPSC CSAT - 2023) 0 7 8 9 Solution: Ans.(3) 199/(1+9+9) = Least, D = 199…

If ABC and DEF are both 3-digit numbers such that A, B, C, D, E and F are distinct non-zero digits such that ABC + DEF = 1111, then what is the value of A + B + C + D + E + F ?

By admin February 20, 2025

(UPSC CSAT - 2023) 28 29 30 31 Solution: Ans.(4) ABC + DEF = 1111…

What is the unit digit in the expansion of

By admin February 20, 2025

(57242)9×7×5×3×1 (UPSC CSAT - 2023) 2 4 6 8 Solution: Ans.(1) When 9×7×5×3×1 is…

What is the remainder when 85 × 87 × 89 × 91 × 95 × 96 is divided by 100?

By admin February 20, 2025

(UPSC CSAT - 2023) 0 1 2 4 Solution: Ans.(1) 100 = 5×5×4 The expression…

For any choices of values of X, Y and Z, the 6-digit number of the form XYZXYZ is divisible by

By admin February 20, 2025

(UPSC CSAT - 2023) 7 and 11 only 11 and 13 only 7 and 13…

A 3-digit number ABC, on multiplication with D gives 37DD where A, B, C and D are different non-zero digits. What is the value of A + B + C ?

By admin February 15, 2025

(UPSC CSAT - 2023) 18 16 15 Can’t be determined due to insufficient data. Solution:…