Answer
0.6
Work Step by Step
We evaluate the expression by substituting $a=0.4$ and $b=0.6$ throughout the expression and simplifying:
$ab+b^{2}$
=$(0.4)(0.6)+(0.6)^{2}$
=$(\frac{4}{10})(\frac{6}{10})+(\frac{6}{10})^{2}$
=$(\frac{4\times6}{10\times10})+(\frac{6^{2}}{10^{2}})$
=$(\frac{24}{100})+(\frac{36}{100})$
=$(\frac{24+36}{100})$
=$(\frac{60}{100})$
=$0.6$