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Sub 505 Level|   Arithmetic|      
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Bunuel
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The tens digit of a two-digit number is twice as large as the units 20 Apr 2017, 01:22
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5% (low)

Question Stats:

86% (01:36) correct 14% (02:15) wrong based on 126 sessions

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The tens digit of a two-digit number is twice as large as the units digit. If the digits are reversed, the new number is 36 less than the original number. What is the original number?

A. 4
B. 8
C. 42
D. 48
E. 84
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E
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The tens digit of a two-digit number is twice as large as the units 20 Apr 2017, 03:15
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Bunuel
The tens digit of a two-digit number is twice as large as the units digit. If the digits are reversed, the new number is 36 less than the original number. What is the original number?

A. 4
B. 8
C. 42
D. 48
E. 84

Tried it without any calculations
Its a a two-digit number - options A and B are out
If the digits are reversed, the new number is 36 less than the original number - options C and D are out

Double check option E ====> 84 - 48 = 36

Hence option E is correct
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The tens digit of a two-digit number is twice as large as the units 20 Apr 2017, 03:34
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Bunuel
The tens digit of a two-digit number is twice as large as the units digit. If the digits are reversed, the new number is 36 less than the original number. What is the original number?

A. 4
B. 8
C. 42
D. 48
E. 84

10 x+ y - 10 y - x = 36

9x - 9y = 36
x-y = 4

0 4 - not possible as tens digit is twice units digits
1 5 - not possible as tens digit is twice units digits
2 6 - not possible as tens digit is twice units digits
3 7 - not possible as tens digit is twice units digits
4 8 - possible
5 9 - not possible as tens digit is twice units digits

48 or 84 choices D/E

as tens digit is twice only 84 is possible
48 would be tens digit is half units digit

E
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The tens digit of a two-digit number is twice as large as the units 20 Apr 2017, 06:41
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10x+ y - 10y - x = 36
9x - 9y = 36
x-y = 4
Given x =2y, hence 2y-y=4=> y=4 and x=8
Hence 10*8 + 4 = 84
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The tens digit of a two-digit number is twice as large as the units 20 May 2017, 03:54
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This particular question seems to be made to work through options.

Since its a two digit number, A and B are eliminated.
Tens digit is twice the units digit, not vice versa. So D is eliminated.
Now we are left with 42 and 84.

Try 42. 42-24=18, not 36. Eliminated.

So only option left is E, which is the answer.
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