Heat is supplied to a monoatomic ideal gas at a constant rate of...

For a monoatomic ideal gas undergoing an isobaric process, the molar heat capacity at constant pressure is $C_p = \dfrac{5}{2}R$.

The heat supplied is given by $dQ = nC_pdT = \dfrac{5}{2}nRdT$.

The work done by the gas during expansion is $dW = pdV = nRdT$.

Taking the ratio of work done to heat supplied:
$\dfrac{dW}{dQ} = \dfrac{nRdT}{\dfrac{5}{2}nRdT} = \dfrac{2}{5}$

Differentiating with respect to time $t$, we get the relationship between their rates:
$\dfrac{dW}{dt} = \dfrac{2}{5} \dfrac{dQ}{dt}$

Given that the rate of heat supplied is $\dfrac{dQ}{dt} = 150\text{ W}$:
$\dfrac{dW}{dt} = \dfrac{2}{5} \times 150\text{ W} = 60\text{ W}$

Answer: $60\text{ W}$