Q. 14.2( 72 Votes )

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

Answer :

We know that. if a number is a multiple of 9, then the sum of its digits will be divisible by 9

Sum of digits of 21*y*5 = 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, 27, and so on …

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

y = 9 - 8

y = 1

Therefore, *y* should be 1 only

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If x + y + z = 6 and z is an odd digit, then the three-digit number xyz is

NCERT - Mathematics ExemplarTest the divisibility of each of the following numbers by 11:

(i) 22222

(ii) 444444

(iii) 379654

(iv) 1057982

(v) 6543207

(vi) 818532

(vii) 900163

(viii) 7531622

RS Aggarwal - MathematicsTest the divisibility of each of the following numbers by 4:

(i) 134

(ii) 618

(iii) 3928

(iv) 50176

(v) 39392

(vi) 56794

(vii) 86102

(viii) 66666

(ix) 99918

(x) 77736

RS Aggarwal - MathematicsTest the divisibility of each of the following numbers by 8:

(i) 6132

(ii) 7304

(iii) 59312

(iv) 66664

(v) 44444

(vi) 154360

(vii) 998818

(viii) 265472

(ix) 7350162

RS Aggarwal - MathematicsTest the divisibility of each of the following numbers by 9:

(i) 327

(ii) 7524

(iii) 32022

(iv) 64302

(v) 89361

(vi) 14799

(vii) 66888

(viii) 30006

(ix) 33333

RS Aggarwal - MathematicsTest the divisibility of each of the following numbers by 5:

(i) 95

(ii) 470

(iii) 1056

(iv) 2735

(v) 55053

(vi) 35790

(vii) 98765

(viii) 42658

(ix) 77990

RS Aggarwal - MathematicsTest the divisibility of each of the following numbers by 3:

(i) 83

(ii) 378

(iii) 474

(iv) 1693

(v) 60005

(vi) 67035

(vii) 591282

(viii) 903164

(ix) 100002

RS Aggarwal - MathematicsTest the divisibility of each of the following numbers by 10:

(i) 205

(ii) 90

(iii) 1174

(iv) 57930

(v) 60005

RS Aggarwal - MathematicsWhich of the following numbers are divisible by 9?

(i) 524618

(ii) 7345845

(iii) 8987148

RS Aggarwal - Mathematics