Answer
Sequence: $2,3,4,5,6,7$
Total number of surfers: $27$
Work Step by Step
Given,
No. of surfers in top row : $2 = 1 + 1$
No. of surfers in second row : $3= 2 + 1$
No. of surfers in third row : $4 = 3+1$
Similarly,
No. of surfers in nth row : $n+1$
No. of surfers in 4th row : $4+1 = 5$
No. of surfers in 5th row : $5+1 = 6$
No. of surfers in 6th row : $6+1 = 7$
Sequence: $2,3,4,5,6,7$
Total number of surfers
$S_{6}=2+3+4+5+6+7$
$S_{6}= 27$
