a,b,c

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a,b,c

by shashank.ism » Mon Feb 08, 2010 11:02 am
Three elements a, b and c are selected from the set A = 2, 3, 5, 6, 7 to form a three-digit number 'abc', where a < b < c. Similarly, two elements p and q are selected from the set B = 0, 1, 8, 9 to form a two-digit number 'pq', where p > q. Let, M be the total number of all the possible values of 'abc' and N be the total number of all the possible values of 'pq'. What is the value of (M - N)?


a) 7
b) 6
c) 5
d) 4
e) 1
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by harsh.champ » Mon Feb 08, 2010 11:05 am
shashank.ism wrote:Three elements a, b and c are selected from the set A = 2, 3, 5, 6, 7 to form a three-digit number 'abc', where a < b < c. Similarly, two elements p and q are selected from the set B = 0, 1, 8, 9 to form a two-digit number 'pq', where p > q. Let, M be the total number of all the possible values of 'abc' and N be the total number of all the possible values of 'pq'. What is the value of (M - N)?


a) 7
b) 6
c) 5
d) 4
e) 1
The value of M is 10 as ten distinct numbers 'abc' are possible:
235, 236, 237, 256, 257, 267, 356, 357, 367 and 567
and the value of N is 6 as
only six distinct numbers 'pq' are possible:
10, 80, 90, 81, 91 and 98[spoiler] Hence (M - N) = 4.
Hence (D) is the correct option.[/spoiler]
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