The given series is in the below pattern,
First term = 3
Second term = First term × 2.5
⇒ Second term = 3 × 2.5 = 7.5 ;
Third term = Second term × 2
⇒ Third term = 7.5 × 2 = 15 ;
Fourth term = Third term × 2.5
⇒ Fourth term = 15 × 2.5 = 37.5 ;
Fifth term = Fourth term × 2
⇒ Fifth term = 37.5 × 2 = 75 ;
Sixth term = Fifth term × 2.5
⇒ Sixth term = 75 × 2.5 = 167.5; 167.5 is wrong. It should be 187.5.
Seventh term = Sixth term × 2
⇒ Seventh term = 187.5 × 2 = 375 ;
Hence, 167.5 is wrong. It should be 187.5.
