Banyaknya bilangan kelipatan 3 dan 5 antara 10 dan 200

Kelipatan 3= 12,15,18,21,24,27,30,33,36,39,42,45,48,51,54,57,60,63,66,69,72,75,
78,81,84,87,90,93,96,99,102,105,108,111,114,117,120,123,126,129,132,
135,138,141,144,147,150,153,156,159,162,165,168,171,174,177,180,183,186,189,192,195,198

kelipatan 5=
15,20,25,30,35,40,45,50,55,60,65,70,75,80,85,90,95,100,105,110,115,120,125,130,135,140,145,150,155,160,165,170,175,180,185,190,195

banyaknya kelipatan 3=  63
banyaknya kelipatan 5= 37

coba kamu hitung lagi..

Kelipatan 3= a= 12, b=3, Un= 198
kelipatan5= a= 15, b=5, Un= 195
Un1= a+(n-1)b
198= 12+(n-1)3
198-12=3n-3
186=3n-3
3n=186+3
3n=189
n=189:3= 63
Un2=a+(n-1)b
195= 15+(n-1)5
195-15=5n-5
180=5n-5
5n= 180+5
n=185÷5
n=37
Jadi bnyak kelipatam 3dan 5 antara 10 dan 200= 63+37=100 bilangan

semoga bener ya^^
kalau menurut aku sih begitu