Math, asked by harshraj62300, 8 months ago

The sum of the digits of a 2-digit number is 7. If the digits are reversed, the new number increased by 3 equals
4 times the original number. Find the original number.​

Answers

Answered by firdousnida05
2

Answer:

Here sum of two digits equals to 7

possible two digits are = (1,6), (2,5),(3,4)

When the digits are reversed and increased by 3

new numbers formed

61 = 61+3 = 64

52= 52+3=55

43 = 43+3= 46

Now 4 times original number

16 *4 = 64

25*4=100

43*4 = 172

Hence cleary original number is (1,6) that is 16

Answered by Anonymous
1

Let x be the digit at ten's place and y be the digit at unit place.

 \sf \therefore \: The  \: number \:  =  \: 10 \: x + y

 \sf \: Sum  \: of  \: its  \: digits = x + y

 \sf \: On \:  reversing \:  the  \: digits,

 \sf \: The \:  number \:  becomes  \: 10  \: y + x.

 \sf \: A/Q, \\   \sf \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \:  \: x + y =  7  \\  \sf \: and,  \:  \:  \:  \:  \: \:  \:  \:  \:  \:  \:  \:  \:   \:  \: 10y + x + 3 = 4(10x + y) \\  \\  \sf \red{x + y = 7 }\:  \:  \:   \:  \:   \\  \sf \: 10y + x + 3 = 4(10x + y) \\  \sf \implies \: 10y + x + 3 = 40x + 4y \\  \sf \implies \: 10y - 4y + x - 40x = 3 \\  \sf \implies \red{6y - 39x = 3} \:  \:  \:  \:  \blue{} \\  \\  \\ \sf \: x + y = 7 \:  \:   \red{\times 6} \\   \sf  \: 6x + 6y = 42 \:  \:  \:  \:  \blue{eq.(i)}\\ \\  \sf \: 6y - 39x = 3 \:  \:  \red{ \times 1} \\   \sf \: 6y - 39x = 3 \:  \:  \blue{...eq.(ii)} \\  \\  \sf \: on \: solving \: we \: get \:  -  \\  \sf \: x = 1 \:  \:  \:  \:  \:  \:  \: \: y = 6 \\  \\  \sf \therefore \: Required  \: number = 10x + y  \\  \sf \:  =  \: 10 \times 1 + 6 \\   \boxed{ \red{ \underline{ \sf \: =  16 \:  \: ....(ans) }}}

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