Question

Equal masses of paraffin and water are mixed in a container of negligible
thermal capacity. Initial temperature of water is 80

Answer 1

$Q_1=Q_2,$

$c_1m_1(80-t)=\lambda m_2+c_2m_2(t-20),$

$m_1=m_2,$

$t=\frac{80c_1+20c_2-\lambda}{c_1+c_2}=53°C.$