To find the work done against friction, we use the principle of conservation of energy. The total work done ($W_{total}$) by an external force to move the block up the incline is equal to the increase in the block's gravitational potential energy ($\Delta U$) plus the work done against dissipative forces like friction ($W_{friction}$).

1. Calculate the increase in Potential Energy (\Delta U): The potential energy gained by raising a mass $m$ to a height $h$ is given by the formula $U = mgh$ , . $\Delta U = 2 \text{ kg} \times 10 \text{ m/s}^2 \times 10 \text{ m} = 200 \text{ J}$

2. Calculate work done against friction ($W_{friction}$): Using the energy balance equation: $W_{total} = \Delta U + W_{friction}$ $300 \text{ J} = 200 \text{ J} + W_{friction}$ $W_{friction} = 300 \text{ J} - 200 \text{ J} = 100 \text{ J}$

Thus, 100 J of the total work was used to overcome friction.