GregMat, Problem Solving

[vidishas99]

GregMat

Wouldn’t 0 also be a correct answer?
If the unit digit of c is 0, then the unit digit of either a or b, must also be 0

[HoldMyBeer]

New Quant Problem solving question

suppose you got 20 as c —> thus 0 becomes the unit digit , what does it tells you about the unit digit of a and b . All possible combination of a and b that gives c = 20. 1 20 2 10 4 5 No, clear unit digit. Now, if we got 5 as the unit digit of number than with guarantee we can say that either a or b unit digit must be 5. Eg if c = 15 . 1 15 3 5 5 as the unit digit in all cases. Eg 2 ) if c = 225 1 225 3 75 5 45 9 25 15 15 Either a or b will have 5 as a unit digit.

[vidishas99]

Thanks