The numbers a, b, and c are consecutive integers and 0

Question

The numbers a, b, and c are consecutive integers and 0 < a < b < c. If the units digit at c*a is 4, what is the units digit of b?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

rajatchopra1994 · Answer

Explanation:
a, b, and c are consecutive integers.
0 < a < b < c. 
units digit at c*a is 4
4x6 is only possibility
So, unit digits will 4,5,6 
B=5

IMO-E

yashikaaggarwal · Answer

A B C are consecutive no. 
and AC unit digit is 4
so none of the ABC can be with unit digit 0
so the ordered triplet = (1,2,3) (2,3,4) (3,4,5) (4,5,6) (5,6,7) (6,7,8) (7,8,9) 
Unit digits of AC in ordered triplet = (3) (8) (5) (4) (5) (8) (3)

only 4,5,6 triplet have AC unit digit as 4 
So value of B unit digit = 5

Answer is E

GMATinsight · Answer

a, b, and c are consecutive integers and 0 < a < b < c

and the units digit at c*a is 4

i.e a and c are two consecutive Even Integers 
2*4 = 8 i.e. a can NOT be 2
  4*6 = 24 i.e. a can be 4

If a = 4 then  b = 5  and c = 6

Answer: Option E

GMATWhizTeam · Answer

Solution 
 • The units’ digit of  c*a = 4 
 o It means at least one of a and c must be even number. 
• Now, a, b, and c are consecutive integers.
 o So, if a is even then c also must be even, and vice-versa.
o Thus, both a and c are consecutive even integers. 
• As,  0 < a < b < c  
 o This implies that  a < c 
o So, possible values of (unit’s digit of a, unit’s digit of c) are (0, 2), (2, 4), (4, 6), (6, 8) and (8, 0).
o Out of which only unit’s digit of  (4*6) = 4 
  Thus,  (a, c)  can be  (4, 6), (14, 16), (24, 26), (34, 36), ……, etc. 
 Therefore,  (a, b, c)  can be  (4, 5, 6), (14, 15, 16), (24, 25, 26),……, etc. 
 • In all the cases, unit’s digit of b = 5.    
Thus, the correct answer is  Option E.

hsingh3031 · Answer

Only one pair is sufficient for this.

As question states C> B>A>0

So taking 6>5>4>0

This makes 6*4 = 24 where 4 is the unit digit as stated above . So B is 5

The numbers a, b, and c are consecutive integers and 0 < a < b < c. If

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