[endless]

so I have this question
When 1.00 kg lead (specific heat capacity = 0.13 J g -1 C -) at 100.0 C is added to a quantity of water at 28.5C, the final temperature of the lead-water mixture is 35.2 C. What is the mass of water present?

so I got ti of water is 28.5c
tf is 35.2 c
the different is 6.7c
and by knowing the specific heat capacity of lead I got the specific heat capacity of water which is -0.13 J g -1 C -

according to the rule which says q lead=-q surrounding
and now I need the mass ,I tried to get the mass with q=mc(the different between t)

but I get the wrong answer each time

the correct answer should be 300g
but I cant get the correct answer
 

can you tell me please what did I do wrong ?

[AWK]

Heat capacity of water?