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let m = 10a + b
n=10b + a

evaluating option A:

m= 82+ a
10a+b = 82+ a
9a +b= 82

a and b are positive integers therefore
possible values of a,b:
a= 9, b=1
a=8, b=10--- not possible

therefore a=9 and b=1
m=91
A is sufficient!

Evaluating B:

n= 18+ b
10b+a= 18+b
9b+a = 18

a, b are positive integers less than 10
possible values of a,b

b=1, a=9
b=2, a=0- not possible as m would not be a two digit integer

therefore n=19 and m=91

B is sufficient

D is the answer
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m = 10x+y
n = 10y + x

Q: Find the value of m.

Statement 1: m is 82 greater than the tens digit of m.

m = x + 82.
Substituting this in the eqn. for m,

x+82 = 10x + y
9x + y = 82

We cannot find the value of m from this.
Hence, Statement 1 is INSUFFICIENT. AD/BCE

Statement 2: n is 18 greater than the tens digit of n.

n = y + 18
Substituting this in the eqn. for n,

y+18 = 10y + x
x+9y = 18

We cannot find the value of n from this.
Hence, Statement 2 is INSUFFICIENT. AD/BCE

Statement 1 and 2 together:

Combining both the eqn.,

9x + y = 82
x+9y = 18

We know that we can find the value for x and y. Therefore we can find the value for m also.

Hence Statements 1 and 2 together are SUFFICIENT.

The answer is C
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Let's assume m = AB, n = BA

1) m = A + 82 = 10A + B, not sufficient enough

2) n = B + 18 = 10B + A, again not sufficient enough.

1 & 2) m - n = A-B + 82-18 = 9(A-B)

=> 8(A-B) = 64
=> A - B = 8
=> if A = 8, B = 0 and m = 80, n = 8 (this is not possible as both are 2 digit integers)
Also another possibility is,
If A = 9, B = 1 and m = 91, n = 19. This satisfies all the criterias mentioned.

Therefore, answer is (C).

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If m and n are two two-digit positive integers with reversed digits (e.g 26 and 62 are 2 two-digit integers with reversed digits), what is the value of m?

(1) m is 82 greater than the tens digit of m.
Let m = 10a + b
Now 10a + b - a = 82
9a + b = 82
Since both a and b are such that a = 9 and b = 1, above equation suggests that a > b possibly 'a' being maximum and 'b' being minimum.
After checking, only for a = 9 and b = 1 satisfy the given condition.
Hence m = 91 where 91 - 9 = 82

SUFFICIENT.

(2) n is 18 greater than the tens digit of n.
Let n = 10b + a
Now, 10b + a - b = 18
9b + a = 18
Since both a and b are such that a = 0, 9 and 1 ≤ b ≤ 2, above equation suggests that possible solutions are for a = 0 and b = 2 OR a = 9 and b = 1.
After checking, both n = 20 and n = 19 satisfy the given condition.
So m = 91, since m being a two digit number m = 2 is not possible.

SUFFICIENT.

Answer D.
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IMO: B
Lets say:
n=ab=10a+b
m=ba=10b+a

m=?

1)m=82+b
10b+a=82+b
9b+a=82
if b=1, a=73;b=2, a=64 and so on. Not Sufficient
2)n=a+18
10a+b=a+18
9a+b=18
Only one set satisfies the above equation: a=1 and b=9. Therefore, m=91. Sufficient
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m =xy (two-digit integer)
n= yx (two-digit integer) —> with reversed integer .

—> xy = 10x+ y
—> yx= 10y+ x

(Statement1):
10x+ y = x+82
9x+ y = 82
(x and y —> 1,2....8,9)
—> in order y to be integer from 1 to 9, x must be only equal to 9.
( if x= 8, then y will be equal to 10, —> y cannot be 10.)

Well, x should be 91.
Sufficient

(Statement2):
10y+ x = y+18
9y+ x= 18
—> in order x to be integer number from 1 to 9, y should be only equal to 1.( if y=2, then x will be zero(0). —> x cannot be zero(0).

Well n should be 19–> m will be equal to 91.

Sufficient

The answer is D

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(1) m is 82 greater than the tens digit of m.


Possible values for tens digit of m and m are

1.....83
2.....84
3.....85
.
.
.
8....90....Not possible since n is 2 digit number....
9....91


So clearly insufficient


(2) n is 18 greater than the tens digit of n....Clearly insufficient...Since we will get 9 possible vales as above..

Combining both we will get...


m=91
n=19


OA:C

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Let m = xy —> n = yx
—> Value of m = 10x + y and n = 10y + x

(1) m is 82 greater than the tens digit of m.
—> 10x + y - x = 82
—> 9x + y = 82

Possible values of (x, y) = (9, 1) ONLY
—> m = 91 —> Sufficient

(2) n is 18 greater than the tens digit of n.
—> 10y + x - y = 18
—> 9y + x = 18

Possible values of (x, y) = (9, 1) ONLY
—> m = 91 —> Sufficient

IMO Option D

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#1

m is 82 greater than the tens digit of m.
m=91 and 91-9 ; 82
sufficient
#2
n is 18 greater than the tens digit of n.
(10B+A)-B=18
(A,B)=(1,9)
9(1)+(9)=18
sufficeint
IMO D

If m and n are two two-digit positive integers with reversed digits (e.g 26 and 62 are 2 two-digit integers with reversed digits), what is the value of m?

(1) m is 82 greater than the tens digit of m.
(2) n is 18 greater than the tens digit of n.
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My Answer : D.

Statement 1: Sufficient
Since M is a two digit integer (10-99) and 82 greater than its tens digit (a positive integer 1-9), M must be greater than 82. So, Tens digit of M CAN be 8 or 9.
If Tens digit of M is 8, M=8+82=90. So, N will be 09 (one digit) which is not possible because N is TWO digit integer. So, Tens digit of M CAN NOT BE 8.
If Tens digit of M is 9, M=9+82=91. So, N will be 91, a TWO digit integer. So, Tens digit of M Must BE 9 and M=91

Statement 2: Sufficient
Since the tens digit of N is 1-9, N must be 19-27. So, the tens digit of N is either 1 or 2.
If Tens digit of N is 2, N=2+18=20. So, M will be 02 (one digit) which is not possible because M is TWO digit integer. So, Tens digit of N CAN NOT BE 2.
If Tens digit of N is 1, N=1+18=19. So, M will be 91, a TWO digit integer. So, Tens digit of N Must BE 1 and N=19 and M=91
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Quote:
If m and n are two two-digit positive integers with reversed digits (e.g 26 and 62 are 2 two-digit integers with reversed digits), what is the value of m?

(1) m is 82 greater than the tens digit of m.
(2) n is 18 greater than the tens digit of n.

(m,n) = 2-digit positive integers
m = 10A+B
n = 10B+A
1≤(A,B)≤9

(1) m is 82 greater than the tens digit of m. sufic.

(10A+B)-A=82…9A+B=82…(1≤(A,B)≤9)…(A,B)=(9,1)…9(9)+(1)=82

(2) n is 18 greater than the tens digit of n. sufic.

(10B+A)-B=18…9B+A=18…(1≤(A,B)≤9)…(A,B)=(1,9)…9(1)+(9)=18

Answer (D)
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