Given: $40\%$ of $m = a$ and $b = \frac{7a}{10}$

$a = 0.4m$ $b = \frac{7(0.4m)}{10} = \frac{2.8m}{10} = 0.28m$

$112\% \text{ of } m = 1.12m$

$\frac{1.12m}{0.28m} = 4$

$1.12m = 4b$