141 Let the required number be X.
Then, (11 X + 11) = 11 ( X + 1) is divisible by 13, so, X =12
14 Let the 3-digit number be X y z . then,
( 100 X + 10 y + z) – (X + y + z) = 99 X + 9 y = 9 (22 X + y), which is divisible by 9.
143. Putting X =5 and y + 1, we get (3 X + 7 y) = ( 3 x 5 + 7 x 1 ) = 22, which is divisible by 11.
4 x + 5 y = (4 x 5 x 5 x 1 ) = 25, which is not divisible by 11.
X + y + = (5 + 1 + 4) = 9, which is not divisible by 11.
9 x + 4 y (9 x 5 x 4 x 1 ) = 49, which is not divisible by 11..
4 X – 9 y = (4 x 5 – 9 x 1) = 11, which is divisible by 11.
144. 4 a 3
9 8 4 a + 8 = b b- a + 8
13 b 7
Also, 13 b 7 is divisible by 11.
(7 + 3) – ( b + 1 ) = ( 9 =b) ( 9 –b) = 0 b= 9.
B = 9 and a = 1 (a+ b) =10.
145. Required number = (2⁵ - 2 ) =(32 – 2) 30.
146. Required number = product of first three multiples of 3 = (3 x 6 x 9 ) = 162
.
147. On dividing 1000 by 45, we get remainder = 10.
Required number to be added = ( 45 – 10) = 35.
148. On dividing 803642 y 11, we get remainder = 70.
Required number to be added = (11 – 4 ) = 7.
149. On dividing 6709 by 9, we get remainder = 4.
Required number to be subtracted = 4.
150. On dividing 427398 by 15, we get remainder = 3.
Required number to be subtracted = 3.
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