1) The greatest number of four digits which is divisible by 15, 25, 40 and 75 is:

A) 9000

B) 9400

C) 9600

D) 9800

Answer:C) 9600

Explanation:Greatest number of 4-digits is 9999.
L.C.M. of 15, 25, 40 and 75 is 600.
On dividing 9999 by 600, the remainder is 399.
Required number (9999 - 399) = 9600.

2) Find the HCF of
2^{2}×3^{2}×7^{2}, 2×3^{4}×7

A) 128

B) 126

C) 146

D) 434

Answer:B) 126

Explanation:
HCF is Highest common factor, so we need to get the common highest factors among given values. So we got
2×3^{2}×7

3) What will be the LCM of 8, 24, 36 and 54 ?

A) 54

B) 108

C) 216

D) 432

Answer:C) 216

Explanation:LCM of 8-24-36-54 will be
2×2×2×3×3×3 = 216

4)The least number, which when divided by 12, 15, 20 and 54 leaves in each case a remainder of 8 is:

A) 544

B) 548

C) 504

D) 536

Answer:B) 548

Explanation:Required number = (L.C.M. of 12, 15, 20, 54) + 8
= 540 + 8
= 548.

5)Find the greatest number that will divide 43, 91 and 183 so as to leave the same remainder in each case.

A) 4

B) 7

C) 9

D) 13

Answer:A) 4

Explanation:Required number = H.C.F. of (91-43), (183-91) and (183-43)
= H.C.F. of 48, 92 and 140 = 4.