CLASS X_CHAPTER 1_REAL NUMBERS_QUIZ 1

• an integer

• a rational

• an irrational

• a whole number

Three bells ring at intervals of 4, 7 and 14 minutes. All three rang at 6:00 am. When will they ring together again?

• 6:07 am

• 6:14 am

• 6:28 am

• 6:25 am

What is the greatest possible speed at which a man can walk 52 km and 91 km in an exact number of hours?

• (a) 17 km/h

• (b) 7 km/h

• (c) 13 km/h

• (d) 26 km/h

The LCM of the smallest 2-digit number and the smallest composite number is:

• (a) 12

• (b) 4

• (c) 20

• (d) 44

(HCF x LCM) for the numbers 70 and 40 is:

• 10

• 280

• 2800

• 70

If two positive integers p and q can be expressed as p = ab² and q = a³b; a, b being prime numbers, then LCM (p, q) is

• (a) ab

• (b) a²b²

• (c) a³b²

• (d) a³b³

The ratio of HCF to LCM of the least composite number and the least prime number is:

• 1:2

• 2:1

• 1:1

• 1:3

If two positive integers a and b are written as a = x³y² and b = xy³; where x, y are prime numbers, then the result obtained by dividing the product of the positive integers by the LCM(a, b) is

• (a) xy

• (b) xy²

• (c) x³y³

• (d) x²y²

Let a and b be two positive integers such that a = p³q⁴ and b = p²q³, where p and q are prime numbers. If HCF(a,b) = p^mqⁿ and LCM(a,b) = p^rq^s , then (m+n)(r+s)=

• (a) 15

• (b) 30

• (c) 35

• (d) 72

(HCF x LCM) for the numbers 56 and 72 is:

• 8

• 504

• 4032

• 72