model 2 find lcm of numbers Section-Wise Topic Notes With Detailed Explanation And Example Questions

Answer: (c)

LCM of 20, 30 and 40 minutes = 120 minutes

Hence, the bells will toll together again after 2 hours i.e. at 1 p.m.

Answer: (c)

LCM of 3, 4, 5, 6, 7, 8 = 840

11$760/840$ = 10000

Since, the remainder 760 is more than half of the divisor 840.

∴ The nearest number

= 10000 + (840 – 760) = 10080

Answer: (b)

Using Rule 5,

Here, Divisor – remainder = 1

e.g., 10 – 9 = 1, 9 – 8 = 1, 8 – 7 = 1

∴ Required number = (L.C.M. of 10, 9, 8) –1

= 360 – 1 = 359

Answer: (c)

∴ 60 = 2 × 2 × 3 × 5

i.e., Numbers = 2, 3, 4 and 5

∴ Required sum = 2 + 3 + 4 + 5 = 14

Answer: (c)

LCM of 25, 50 and 75 = 150

On dividing 43582 by 150, remainder = 82

290$82/150$ = 43582

∴ Required number = 43582 + (150 – 82)

= 43650

Answer: (c)

Using Rule 8,

Greatest n digit number which when divided by three numbers P, Q, R leaves no remainder will be

Required Number = (n – digit greatest number) – R

R is the remainder obtained on dividing greatest n digit number by L.C.M of P, Q, R.

LCM of 10, 15 and 20 = 60

Largest 4-digit number = 9999

∴ 166$39/60$ = 9999

∴ Required number = 9999 – 39

= 9960