Problem Solving

[RiyaR]

If x,y and z are single digit integers and 100(x)+ 1,000(y)+10(z)=N. What is the unit's digit of the number N?
A) 0
B) 1
C) x
D) y
E) z

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Hi RiyaR,

This is a "concept" question, meaning that you need to think about what the information "really means" to answer it. It can also be solved by TESTing VALUES.

Let's TEST:

X = 2
Y = 3
Z = 4

100(2) + 1000(3) + 10(4) = N
200 + 3000 + 40 = N
3240 = N

The question asks for the "unit's digit" (aka the "one's digit"). The unit's digit is 0

Final Answer: A

GMAT assassins aren't born, they're made,
Rich

[GMATinsight]

If x,y and z are single digit integers and 100(x)+ 1,000(y)+10(z)=N. What is the unit's digit of the number N?
A) 0
B) 1
C) x
D) y
E) z

A 4 Digit Number ABCD is defined by

1000A + 100B + 10C + D where D is the Unit digit

Here 100(x)+ 1,000(y)+10(z)=N

Unit digit is not there therefore it is bound to be zero

[GMATinsight]

If x,y and z are single digit integers and 100(x)+ 1,000(y)+10(z)=N. What is the unit's digit of the number N?
A) 0
B) 1
C) x
D) y
E) z

A 4 Digit Number ABCD is defined by

1000A + 100B + 10C + D where D is the Unit digit

Here 100(x)+ 1,000(y)+10(z)=N

Unit digit is not there therefore it is bound to be zero

[GMATinsight]

If x,y and z are single digit integers and 100(x)+ 1,000(y)+10(z)=N. What is the unit's digit of the number N?
A) 0
B) 1
C) x
D) y
E) z

ALTERNATE

Here 100(x)+ 1,000(y)+10(z)=N

Unit Digit of 100x = 0
Unit Digit of 1000Y = 0
Unit Digit of 10z = 0

Therefore Unit Digit of N = 0