Answer
See explanation
Work Step by Step
In general, glassware is estimated to be one place past the markings.
a) $128.7\text{ mL}$ glassware: $100\text{ mL}$ graduated cylinder +$ 50\text{ mL}$ buret to read to tenth’s place
b. $18\text{ mL}$ glassware: $25\text{ mL}$ graduated cylinder - read to $0.5$ or $1\text{ mL}$
c. $23.45\text{ mL}$ glassware: $25\text{ mL}$ buret - read to two decimal places
Total volume $= 128.7 + 18 + 23.45 = 170.15 $
So, round the total to 2 significant figures → $170\text{ mL}$
