if the units digital of the three digit positive integer k is not zero, what is the tens digit of k?
1) the tens digit of k+9 is 3
2) the tens digit of k+4 is 2
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Statement 1. the tens digit of k+9 is 3
Since the units digit is not 0, even if the units digit is the lowest i.e. 1, adding 9 to the number will affect the tens digit. Hence the tens digit of k is 2. SUFF
2) the tens digit of k+4 is 2
If the units digit of k is 6 or greater, the tens digit of k+4 will be 1. But if it is between 1 and 5, then the tens digit will be 2. INSUFF.
Answer is A
Since the units digit is not 0, even if the units digit is the lowest i.e. 1, adding 9 to the number will affect the tens digit. Hence the tens digit of k is 2. SUFF
2) the tens digit of k+4 is 2
If the units digit of k is 6 or greater, the tens digit of k+4 will be 1. But if it is between 1 and 5, then the tens digit will be 2. INSUFF.
Answer is A
The answer is A
Consider any three digit number which doesn't have the last digit as 0.
Stmt1 if you add 9 to the number the tens digit becomes 3.
So the tens digit of the number must be 2. Because if you add 9 to the units digit - 1 would get carried over and the tens digit will become 3.
For eg. lets say our number is 525, now if you add 9 to it you get 534.
You can try this for any three digit number but the tens digit has to be 2.
For eg. 521+9, 526+9, 921+9, 225+9.....
The importance of the unit's digit not being 0 is that - if the number was 520 and you added 9. you'll get 529....
>>The tens digit of k has to be 2. stmt1 is suff.
Stmt2 - the tens digit of k+4 is 2
Doesn't give a conclusive answer - lets say the number k is 524 and we add 4, we get 528.
But if the number k is 517 and we add 4 we get 521.
So adding 4 may or may not have an impact on the tens digit. Which is not the case if you add 9 (in that case 1 has to carry over)
>> we can't be sure of the tens digit of k. stmt2 is insuff.
Not sure if that was the greatest explanation...but hope it helps!
Consider any three digit number which doesn't have the last digit as 0.
Stmt1 if you add 9 to the number the tens digit becomes 3.
So the tens digit of the number must be 2. Because if you add 9 to the units digit - 1 would get carried over and the tens digit will become 3.
For eg. lets say our number is 525, now if you add 9 to it you get 534.
You can try this for any three digit number but the tens digit has to be 2.
For eg. 521+9, 526+9, 921+9, 225+9.....
The importance of the unit's digit not being 0 is that - if the number was 520 and you added 9. you'll get 529....
>>The tens digit of k has to be 2. stmt1 is suff.
Stmt2 - the tens digit of k+4 is 2
Doesn't give a conclusive answer - lets say the number k is 524 and we add 4, we get 528.
But if the number k is 517 and we add 4 we get 521.
So adding 4 may or may not have an impact on the tens digit. Which is not the case if you add 9 (in that case 1 has to carry over)
>> we can't be sure of the tens digit of k. stmt2 is insuff.
Not sure if that was the greatest explanation...but hope it helps!