4,9,14,19,... , up to 25ih term T25=4+(25−1)5=4+120=124 3,6,9,12,... , up to 37th term T37=3+(37−1)3=3+108=111 Common difference of Ist series d1=5 Common difference of II nd series d2=3 First common term =9 , and their common difference =15(LCM2. of d1 and d2) then common terms are 9,24,39,54,69,84,99