Atitration of 25.0ml of an x m hcl solution with 0.15m naoh starts at a burette reading for naoh of 0.20ml . thr burette reading of the end point is 24.10ml. what is the volume of naoh dispensed?

Burette is a very accurate measuring instrument when adding solutions and has a measurement error of 0.05 mL. 
Small volumes of solutions can be transferred from the burette at a controllable rate. 
In this instance NaOH is in the burette.
Initial reading of NaOH is 0.20 mL 
end point is the point at which the chemical reaction reaches completion. In acid base reactions, end point is when all the H⁺ ions have reacted with OH⁻ ions. 
final reading of NaOH is 24.10 mL
to find the volume of NaOH dispensed we have to find the difference between final reading and initial reading 
volume of NaOH added = 24.10 mL - 0.20 mL = 23.90 mL
volume of NaOH dispensed is 23.90 mL

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer