The amount of heat needed to increase the temperature of a substance by 
is given by
where
m is the mass of the substance
the specific heat capacity
the increase in temperature
In our problem, the mass of the water is m=750 g, the specific heat is
and the amount of heat supplied is 
, so if we re-arrange the previous formula we find the increase in temperature of the water:
where
m is the mass of the substance
In our problem, the mass of the water is m=750 g, the specific heat is