For which battery is the total sales of all the seven years the maximum?
32 AH
The total sales (in thousands) of all the seven years for various batteries are:
For 4 AH, =75+90+96+105+90+105+115=676
For 7 AH, =144+126+114+90+75+60+85=694
For 32 AH,=114+102+75+150+135+165+160=901
For 35 AH,=102+84+105+90+75+45+100=601
For 55 AH,=108+126+135+75+90+120+145=799
Clearly, sales is maximum in case of 32 AH batteries.