1000+ TNPSC Aptitude Questions with Solutions - 1

Ans: B

Let the numbers be 13a and 13b.

Then, 13a × 13b = 2028 ⇒ ab = 12.

Now, co-primes with product 12 are (1, 12) and (3, 4).

So, the required numbers are (13 × 1, 13 × 12) and (13 × 3, 13 × 4).

Clearly, there are 2 such pairs.

Ans: C

The time after which the bells will ring together is the L.C.M. of 5, 6, 8, 12 and 20 seconds, i.e., 120 seconds.

The number of times they will toll together in one hour.

= $$({3600} / {120})$$ + 1 = 30 + 1 = 31.

Ans: C

L.C.M. of 4, 6, 10, 15 = 60

Greatest number of five digits which is divisible by 60 = 99960.

∴ Required number = 99960 + 3 = 99963.

Ans: B

L.C.M. of 2, 3, 4, 5, 6, is 60.

Now 60 x 1 + 1 = 61 not divisible by 7.

60 x 2 + 1 = 121 not divisible by 7.

60 x 5 + 1 = 301 divisible by 7.

Ans: A

Required number = H.C.F. of (91 - 43), (183 - 91) and (183 - 43)

                           = H.C.F. of 48, 92 and 140 = 4.