Question

DATA a P.A ( 6,13,20,27,34.41,48,55...) deternine

A) a 80
B) a 150
C) a 220
D) a 300

Answer 1

$P.A ( 6,13,20,27,34.41,48,55...)\\\\\\ a_{1} =6\\\\r=7\\\\\\\\ Formula\to a_{n} = a_{1} +(n-1)*r \\\\\\\\ a) a_{80} =?\\ n=80\\\\ a_{80} = 6 +(80-1)*7\to \\a_{80} = 6 +79*7\to\\ a_{80} = 6 +553\to\\ a_{80} = 559\\\\\\ b) a_{150} =?\\n=150\\ \\a_{150} = 6 +(150-1)*7\to\\ a_{150} = 6 +149*7\to\\ a_{150} = 6 +1043\to \\ a_{150}=1049\\ \\\\c) a_{220}=?\\ n=220\\ \\a_{220} = 6 +(220-1)*7\to\\ a_{220} = 6 +219*7\to\\ a_{220} = 6 +1553\to \\ a_{220} = 1559$





$d) a_{300} =?\\ n=300\\\\ a_{300} = 6 +(300-1)*7\to \\a_{300} = 6 +299*7\to \\ a_{300} = 6 +2093\to \\ a_{300} = 2099$