Question 22958
speed=	5 yards per second=5*3=		15	fps				
time = 1 mt. 16 sec.= 60 +16 =			76	sec.				
distance covered =speed *time =			15*76	=	1140	feet		
		POTATOES NUMBERS						
basket		1	2	3	4	5	6	7......
distance	10	4	4	4	4	4	4......
totdis.frm bask.10	14	18	22	26	30	34......
distance covered to basket potato 			1	=	10+10	=	2*10	
distance covered to basket potato 			2	=	14+14	=	2*14	
distance covered to basket potato 			3	=	18+18	=	2*18	
distance covered to basket potato 			4	=	22+22	=	2*22	
......................................................................
......................................................................
TOTAL DISTANCE COVERED=2*10+2*14+2*18....=2(10+14+18+....)=1140
this is an arithmatic progression.FIRST TERM =A =10
COMMON DIFFERENCE =D=4
NO.OF TERMS = N = ?
SUM = 1140/2=570 FEET = (N/2){2A+(N-1)D)=(N/2)(2*10+(N-1)4)=(N/2)(20+4N-4)=
(N/2)(4N-16)=2N(N-4)=570
N(N-4)=570/2
N^2-4N-285=0
N^2-19N+15N-285=0
N(N-19)+15(N-19)=0
(N-19)(N+15)=0
N-19=0
N=19
SO HE PICKS 19 POTATOES