Question Number 192103 by Spillover last updated on 08/May/23
Answered by otchereabdullai@gmail.com last updated on 08/May/23
$${the}\:{most}\:{important}\:{thing}\:{to}\:{know}\:{is} \\ $$$${we}\:{cant}\:{start}\:{the}\:{number}\:{with}\:{zero} \\ $$$${since}\:{is}\:{a}\:{four}\:{digit}\:{mumber}\:{without} \\ $$$${repetition} \\ $$$${the}\:{first}\:{can}\:{be}\:{chosen}\:{in}\:\mathrm{5}\:{ways}, \\ $$$${the}\:{second}\:{can}\:{be}\:{chosen}\:{in}\:\mathrm{5}\:{ways} \\ $$$${the}\:{third}\:{can}\:{be}\:{chosen}\:{in}\:\mathrm{4}\:{ways} \\ $$$${the}\:{forth}\:{can}\:{be}\:{chosen}\:{in}\:\mathrm{3}{ways} \\ $$$${so} \\ $$$${number}\:{of}\:{ways}\:=\mathrm{5}×\mathrm{5}×\mathrm{4}×\mathrm{3} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\mathrm{300}{ways} \\ $$