Cylindrical cup: radius $r=4$ cm, height $h=7$ cm. Hemispherical cup: radius $R=7$ cm.

(i) $$CSA(\text{cylinder})=2\pi rh=2\times\frac{22}{7}\times4\times7=176\ cm^2$$

(ii) $$\text{Inner surface area (hemisphere)}=2\pi R^2=2\times\frac{22}{7}\times49=308\ cm^2$$

(iii)(a) $$V(\text{cylinder})=\pi r^2h=\frac{22}{7}\times16\times7=352\ cm^3$$ $$V(\text{hemisphere})=\frac23\pi R^3=\frac23\times\frac{22}{7}\times343=\frac{2156}{3}\approx718.67\ cm^3$$ Difference $=718.67-352\approx366.67\ cm^3\left(=\frac{1100}{3}\ cm^3\right)$

OR

(iii)(b) Total volume $=2(352)+718.67=704+718.67\approx1422.67\ cm^3\left(=\frac{4268}{3}\ cm^3\right)$