# CAT Number System Questions for Practice

Question 1:
When you reverse the digits of the number 13, the number increases by 18. How many other two digit numbers increase by 18 when their digits are reversed?
Topic: Basics

[1] 5
[2] 6
[3] 7
[4] 8

Question 2:
Suppose you have a currency, named Miso, in three denominations: 1 Miso, 10 Misos and 50 Misos. In how many ways can you pay a bill of 107 Misos?
Topic: Basics

[1] 17
[2] 16
[3] 18
[4] 15

Question 3:
A confused bank teller transposed the rupees and paise when he cashed a cheque for Shailaja. Giving her rupees instead of paise and paise instead of rupees. After buying a toffee for 50 paise, Shailaja noticed that she was left with exactly three times as much as the amount on the cheque. Which of the following is a valid statement about the cheque amount?
Topic: basics

[1] Over Rupees 13 but less than Rupees 14
[2] Over Rupees 7 but less than Rupees 8
[3] Over Rupees 22 but less than Rupees 23
[4] Over Rupees 18 but less than Rupees 19

Question 4:
How many pairs of positive integers m, n satisfy $\frac{1}{m} + \frac{4}{n} = \frac{1}{2},$ , where, ‘n’ is an odd integer less than 60?
Topic: Factors

[1] 6
[2] 4
[3] 7
[4] 5

Question 5:
The question is followed by two statements A and B. Indicate your response based on the following directives.

The average weight of a class of 100 students is 45 kg. The class consists of two sections, I and II, each with 50 students. The average weight, WI , of Section I is smaller than the average weight WII , of the Section II. If the heaviest student say Deepak, of section II is moved to Section I, and the lightest student, say Poonam, of Section I is moved to Section II, then the average weights of the two sections are switched, i.e., the average weight of Section I becomes WII and that of Section II becomes WI . What is the weight of Poonam?

A: WII – WI =1.0.

B: Moving Deepak from Section II to I (without any move I to II) makes the average weights of the two sections equal.

Topic: DS

[1] The questions can be answered using A alone but not using B alone.
[2] The question can be answered using B alone but not using A alone.
[3] The question can be answered using A and B together, but not using either A or B alone.
[4] The question cannot be answered even using A and B together