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Quantative aptitude problems

RishebhKumar (Studying) (128 Points)

12 May 2012

Q1.the sum of a digit of a two digit number is 10.If 18 is subtracted from it the digits in the resulting number will be equal.the number is .........?

Please teach me how to solve this....

thanks

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4 Replies

(Guest)

answer is 73. 7+3=10. 73-18=55

intermediate(ipc)course (no) (1460 Points)
Replied 13 May 2012

let two digits are X & Y

AS PER QUESTION,

X + Y = 10 ---------------------------(1)

X - 18 = Y

OR, X -Y = 18 -----------------------(2)

AFTER SOLVING THIS EQUATION,

U GET, X = 14 & Y = -4.

Tejaswi Kasturi (student-cpt) (427 Points)
Replied 13 May 2012

/forum/cpt-maths-question-200005.asp

check this link out the answer is extensiively discussed here

Raja Panduranga CA, CS, LLB (Cheif Finance Officer) (581 Points)
Replied 13 May 2012

Let x = 10's digit of a two digit number
Let y = units digit
Let z = the resulting equal digits
:
Write an equation for each statement:
:
"the sum of a two digit number is 10."
x + y = 10
or
y = (10-x)
:
" if 18 be subtracted from it, the digits in the resulting number will be equal."
10x + y - 18 = 10z + z
10x + y = 11z + 18
:
Substitute (10-x) for y
10x + (10-x) = 11z + 18
10x - x = 11z + 18 - 10
9x = 11z + 8
:
The single digit integer values for x and z are limited to x=7 and z=5 in this equation:
x = 7, y = 3, z = 5
:
The number is 73
:
Check in the statement:
"if 18 be subtracted from it, the digits in the resulting number will be equal."
73 - 18 = 55