number systems Model Questions & Answers, Practice Test for ssc chsl tier 1
The digits of a three-digit number A are written in the reverse order to form another three-digit number B. If B > A and B– A is perfectly divisible by 7, then which of the following is necessarily true ?
Answer: (c)
Let the 3 digits of number A be x, y and z
Hence A = 100x + 10y + z
On reversing the digits of number A,
we get the number B i.e., z y x.
∴ B = 100z + 10y + x
As B > A ⇒ z > x ...(i)
B – A = 99z – 99x = 99(z – x)
As 99 is not divisible by 7
so (z – x) has to be divisible by 7. ...(ii)
Using (i) & (ii), the only possible values of z and x are (8, 1) and (9, 2)
So the minimum and maximum range of A are 108 and 299, which Î106 < A < 305
A six digit number which is consisting of only one digits either 1, 2, 3, 4, 5, 6, 7, 8 or 9, e.g., 111111, 222222... etc. This number is always divisible by :
Answer: (d)
Since the 7, 11 and 13 all are the factors of such a number so (d) is the correct answer.
On dividing 2272 as well as 875 by 3-digit number N, we get the same remainder. The sum of the digits of N is:
Answer: (c)
Clearly, (2272 – 875) = 1397, is exactly divisible by N.
Now, 1397 = 11 × 127
∴ The required 3-digit number is 127, the sum of whose digits is 10.
If the number 517 * 324 is completely divisible by 3, then the smallest whole number in place of * will be:
Answer: (a)
Sum of digits = (5 + 1 + 7 + x + 3 + 2 + 4) = (22 + x), which must be divisible by 3.
∴ x = 2.
A number consists of two digits, whose sum is 7. If the digits are reversed, the number is increased by 27. The product of digits of the number is
Answer: (b)
Let the number be (10x + y)
According to question
⇒ x + y = 7 --- (i)
(10y + x) – (10x + y) = 27
⇒ 9(y – x) = 27
⇒ y – x = 3 --- (ii)
From eq (i) and (ii)
x = 2; y = 5
so x × y = 2 × 5 = 10
So, option (c) is correct.
ssc chsl tier 1 IMPORTANT QUESTION AND ANSWERS
ssc chsl tier 1TOPICS
Read More
ssc chsl tier 1 2024 SYLLABUS
Read More
ssc chsl tier 1 2024 NOTIFICATION
Read More
All Exams
-
SSC
»
Model MCQ Test [Syllabus Wise], Syllabus, Notification -
BANKING
»
Model MCQ Test [Syllabus Wise], Syllabus, Notification -
TNPSC
»
Model MCQ Test [Syllabus Wise], Syllabus, Notification
RECENT BLOGS
Recently Added Subject & Categories For All Competitive Exams
100+ Quadratic Equation Questions Answers PDF for Bank
Quadratic Equation multiple choice questions with detailed answers for IBPS RRB SO. more than 250 Attitude practice test exercises for all competitive exams
Continue Reading »
IBPS Aptitude Linear Equations MCQ Questions Answers PDF
Linear equations multiple choice questions with detailed answers for IBPS RRB SO. more than 250 Attitude practice test exercises for all competitive exams
Continue Reading »
New 100+ Compound Interest MCQ with Answers PDF for IBPS
Compound Interest verbal ability questions and answers solutions with PDF for IBPS RRB PO. Aptitude Objective MCQ Practice Exercises all competitive exams
Continue Reading »
100+ Mixture and Alligation MCQ Questions PDF for IBPS
Most importantly Mixture and Alligation multiple choice questions and answers with PDF for IBPS RRB PO. Aptitude MCQ Practice Exercises all Bank Exams
Continue Reading »