Q=10,08кДж=10080Дж
Q=cm(t2-t1)
c=Q/m(t2-t1) = 10080 / 0,6*8 = 2100Дж/кг°С
n=Q1*100%/Q2
n=cm(t2-t1)*100%/Lm
25%=4200*50*90*100%/10000000m
250000000m=1890000000
m=7,56кг
Ответ: 7,56кг