If in city A, the ratio of male graduates to female graduates is 3 : 4 and total graduates in the city are 70% of total population. Find population of females who are not graduate.

total graduate population = $frac{{70}}{{100}} imes left( {300 + 400} ight)$

= 490

Female graduate population = $frac{4}{7} imes 490 = 280$

Female population who is not graduate

= 400−280=120