Question

Решите номер 7 (а) номер 8 (а) ...........

Answer 1

7а
$B=A\cdot(1+ \frac{p}{100}) \\\ B=120\cdot(1+ \frac{20}{100})=120\cdot(1+ 0.2)=120\cdot1.2=144$

8a
$A=B\cdot(1- \frac{p}{100}) \\\ A=120\cdot(1- \frac{15}{100})=120\cdot(1- 0.15)=120\cdot0.85=102$