A metal blick is made from a mixture of 2.4 kg of aluminium 1.6 kg of brass and 0.8 kg of copper. The amount of heat required to raide the temperature of this block from `20^(@)C` to `80^(@)C` is (specific heats of aluminium brass and copper are `0.216, 0.0917 cal kg^(-1)``^(@)C^(-1)` respectively)