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Evaluate the missing digit (Posted on 2018-01-29) Difficulty: 2 of 5
If the tens digit (second from the right)
of the product p = 2z7 * 39 is 9,
find the digit z.

No Solution Yet Submitted by Ady TZIDON    
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Solution Solution Comment 1 of 1
2z7 * 39
= 2z7*9 + 2z7*30
The tens digit of the first product is 9z+6 
The tens digit of the second product is 1
So the tens digit of p is the unit digit of 9z+7
9z+7 ends in 9
9z ends in 2
9z = 72
z=8

check:
287*39 = 11193

  Posted by Jer on 2018-01-29 09:48:02
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