Question

ex 16.2 class VIII maths question 1​

Answer 1

Step-by-step explanation:

1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?

1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?Solution:

1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?Solution:Suppose 21y5 is a multiple of 9.

1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?Solution:Suppose 21y5 is a multiple of 9.Therefore, according to the divisibility rule of 9, the sum of all the digits should be a multiple of 9.

1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?Solution:Suppose 21y5 is a multiple of 9.Therefore, according to the divisibility rule of 9, the sum of all the digits should be a multiple of 9.That is, 2+1+y+5 = 8+y

1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?Solution:Suppose 21y5 is a multiple of 9.Therefore, according to the divisibility rule of 9, the sum of all the digits should be a multiple of 9.That is, 2+1+y+5 = 8+yTherefore, 8+y is a factor of 9.

1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?Solution:Suppose 21y5 is a multiple of 9.Therefore, according to the divisibility rule of 9, the sum of all the digits should be a multiple of 9.That is, 2+1+y+5 = 8+yTherefore, 8+y is a factor of 9.This is possible when 8+y is any one of these numbers 0, 9, 18, 27, and so on

1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?Solution:Suppose 21y5 is a multiple of 9.Therefore, according to the divisibility rule of 9, the sum of all the digits should be a multiple of 9.That is, 2+1+y+5 = 8+yTherefore, 8+y is a factor of 9.This is possible when 8+y is any one of these numbers 0, 9, 18, 27, and so onHowever, since y is a single digit number, this sum can be 9 only.

1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?Solution:Suppose 21y5 is a multiple of 9.Therefore, according to the divisibility rule of 9, the sum of all the digits should be a multiple of 9.That is, 2+1+y+5 = 8+yTherefore, 8+y is a factor of 9.This is possible when 8+y is any one of these numbers 0, 9, 18, 27, and so onHowever, since y is a single digit number, this sum can be 9 only.Therefore, the value of y should be 1 only i.e. 8+y = 8+1 = 9.

Answer 2

Answer:

Question :If 21y5 is a multiple of 9, where y is a digit, what is the value of y?

Explanation:

If a number is a multiple if 9, then the sum of the digits will be divisible by 9.

Sum of digits of 21y5 = 2+1+y+5=8+y

Hence, 8+y should be a multiple of 9.

This is possible when 8+y is any one of these numbers 0,9,18,27and so on...

However, since y is a single digit number, this sum can be 9 only.

Therefore, y should be 1 only.

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