Answer
$\eta_4 > \eta_3>\eta_2 =\eta_1$
Work Step by Step
We have
$\eta = \frac{W}{Q_1} =\frac{Q_1 -Q_2}{Q_1}$
Therefore,
$\eta _1= \frac{4}{10} =0.4$
$\eta _2= \frac{40}{100} =0.4$
$\eta _3= \frac{6}{10} =0.6$
$\eta _4= \frac{94}{100} =0.94$
Hence
$\eta_4 > \eta_3>\eta_2 =\eta_1$
