The rate of a certain variety of rice increases by 20%. A man gets that variety of rice 3 kg less for ₹630 in comparison with the quantity that he would have got at the old rate. Find the old rate of that variety of rice.
There are 500 students in a school. The boys and girls are in the ratio 7 : 3. If 120 new girls are enrolled in the school, then what will be the ratio of the number of boys to that of girls?