Class 8, Maths, Chapter 16, Exercise 16.2 Solutions
Q.1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?
Q.2. If 31z5 is a multiple of 9, where z is a digit, what is the value of z? You will find that there are two answers for the last problem. Why is this so?
Q.3. If 24x is a multiple of 3, where x is a digit, what is the value of x? (Since 24x is a multiple of 3, its sum of digits 6 + x is a multiple of 3; so, 6 + x is one of these numbers: 0, 3, 6, 9, 12, 15, 18, …. But since x is a digit, it can only be that 6 + x = 6 or 9 or 12 or 15. Therefore, x = 0 or 3 or 6 or 9. Thus, x can have any of four different values.)
Q.4. If 31z5 is a multiple of 3, where z is a digit, what might be the values of z?
