2010/049) Let's say a number ABCDE is such that ABCDE*4=EDCBA. where A,B,C,D,E are no.s between 0 and 9. then ABCDE

AB has to be < 25 because25* 4 = 100 so RHS shall be 6 digit number.
A cannot be 1 as from RHS A has to be even
B is Odd as only multple of 4 *n n < 10 ending with 2 is 12 or 32 which causes odd + 4* n
so AB has to be 21 or 23
if AB = 23 DE >= 92
do D = 9
which is not possible as 4*8 is 2 ending but 4*9 is not

AB = 21
So E = 8
DE *4 should end in 12 so D = 7 as
now number is
so the number = 4*(21078+100C) = 87012+100C
or 84312+400C = 87012+ 100C
300C = 2700 or C =9
so number = 21978 * 4 = 87912