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Using the digits 1, 2, 3, 4, 5, how many even three-digit numbers less than 500 can be formed if each digit can be used more than once?

 Dec 21, 2019
 #1
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a=1;b=1;c=2;p=0; cycle:d=a*100+b*10+c;if(d%2==0 and d<500, goto loop, goto next); loop:printd," ",;p=p+1; next:c++;if(c<6, goto cycle, 0);c=2;b++;if(b<6, goto cycle, 0);b=1;c=2;a++;if(a<10, goto cycle,0);print"Total = ",p

 

OUTPUT: 112  114  122  124  132  134  142  144  152  154  212  214  222  224  232  234  242  244  252  254  312  314  322  324  332  334  342  344  352  354  412  414  422  424  432  434  442  444  452  454  Total =  40 such numbers.

 Dec 21, 2019
 #2
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Five cannot be first ( to be less than 500)

2 or 4  must be last (to be even)

 

Position 1   4 possibles ( 1 2 3 4)

Position2    5 possibles (1 2 3 4 5)

sosition3     2 possibles (2 and 4)

 

4 x 5 x 2 = 40 possible numbers

 Dec 21, 2019

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