Answer:
Step-by-step explanation:
AP 1 : 12, 15 , 18 , 21, 24, 27, 30 , 33 , 36, 39,.....
AP 2 : 17 , 21 , 25 , 29, 33, 37 , 41, 45,.....
AP formed with the common terms: 21, 33, 45 , ......
a = 21 , d = 33-21 = 12 ; n = 100
Sum = [tex]\frac{n}{2}(2a +(n-1)d)[/tex]
[tex]=\frac{100}{2}[2*21+99*12]\\\\=50 * [42+1188]\\\\=50*1230\\\\= 61500[/tex]
