Answer:

126₹ or 170₹

Step-by-step explanation:

1). Hemi sphere Lateral/ Curved Surface Area = 2πR^2

(where R: Outer radius of cup : 17/2 cm.)

2). Hemi sphere is in Cup Shape, So

the remaining surface Area is = π( R^2- r^2)

(where r: Inner radius of cup : 15/2 cm.)

Total Outer Surface Area of Cup : 2πR^2 + π( R^2- r^2)

= 530.97 cm^2

Cost per polishing: 531× 25p. = 126₹

NOTE : There is inside Area of cup = 2π r^2

(where r: Inner radius of cup : 15/2 cm.)

If it is also include this Area, 176.6cm^2

The Answer will be 176.6×25p.= 44.15₹

Total cost will be = 170₹