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Q.

The sum of all three digited numbers that can be formed from the digits 1 to 9 and when the middle digit is perfect square is

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a

1,34,055 (When repetitions are allowed)

b

1,70,555 (When repetitions are allowed)

c

8,73,74 (When repetitions are not allowed)

d

93,387 (When repetitions are not allowed)

answer is A, D.

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Detailed Solution

The value of the number xyz is 100x + 10y + z, where as x and z can be any two of the digits 1 to 9. But y can only be any one of the digits 1, 4, 9.
 Total value of the 3 digit numbers so formed is 

V=100(1+2+3+.+9)93+10(1+4+9)99+(1+2+.+)93

V=121500+11340+1215=134055

When repetitions are not allowed

 7p1(101)91+8p2×10

 7p1(101)94+8p2×40+ 7p1(101)99+8p2×90=93,387

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