ANSWER
[tex] \frac{5a}{3} [/tex]
EXPLANATION
The given fractions are:
[tex] \frac{{a}^{3} + {a}^{2} b}{5a} \times \frac{25}{3b + 3a} [/tex]
We factor to obtain:
[tex]\frac{{a}^{2}(a + b)}{5a} \times \frac{25}{3(a + b)} [/tex]
We cancel the common factors to get:
[tex]\frac{{a}(1)}{1} \times \frac{5}{3(1)} [/tex]
We multiply the numerators and also multiply the denominators to get:
[tex] \frac{5a}{3} [/tex]
Therefore the two fractions simplifies to [tex] \frac{5a}{3} [/tex]