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Re: If a and b are positive integers, what is the units digit of [#permalink]
28 Jul 2015, 14:01
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If a and b are positive integers, what is the units digit of [#permalink]
03 Aug 2015, 10:14
I think it should be A as the question stem states that a & b are positive integers, ruling out the possibility of b being 0.
Your comments please
Not really. Positive integers can also include numbers such as 10, 20, 35 , 77 or even 1000. Having a ,b POSITIVE INTEGERS only means that the selected integers are >0 NOT that their unit's digit is 0 (this may or may not be true as shown below).
Per statement 1, b = 1.25 a
This statement can not be sufficient as you do not know about a.
Take 2 cases:
a= 4, b = 5, units digit = 5
a =16, b = 20, unit's digit = 0 . Hence you get 2 different answers. Thus this statement is not sufficient. _________________