Answer:
172
Explanation:
The no of jumps makes an A.P series whose first term a is 11 and commom difference d is 3.
Any n the term = a + ( n-1 ) d
first term = a
second term a + d
third term a + 2d
n-1 the term = a + (n-2)d
n th term = a + (n-1) d
∑ ( sum of n ) = a + (a +d ) + ( a + 2d ) + ----------------[a +(n-2)d ]+[a+(n-1)d]
∑ = =[a+(n-1)d] +[a +(n-2)d ]+------------------- (a + d) + a
the second series have been written by reversing the term of series
Adding the two series , we get
2∑ = [2a+(n-1)d] +[2a+(n-1)d] + ------------------- [2a+(n-1)d] + [2a+(n-1)d]
∑ = 1/2x n[2a+(n-1)d]
Here n = 8 , a = 11 , d = 3
∑ = 1/2 x 8 x ( 22 + 21)
= .5 x 8 x 43 = 172
