Final answer:
In the class of 90 students, with twice as many boys as girls, there are 30 girls and 60 boys. Rani is 58th from the left which means there are 57 students to her left and 20 boys to her right. There are 47 girls to the left of Rani.
Step-by-step explanation:
Calculating the Number of Girls to the Left of Rani
To solve this problem, we must first determine the total number of boys and girls in the class. We know that there are 90 students in total, and the number of boys is twice the number of girls. Let's denote the number of girls as 'g'. Therefore, the number of boys equals '2g'. The sum of boys and girls should equal the total number of students:
g + 2g = 90
Solving for 'g', we get:
3g = 90
g = 30
This means there are 30 girls and 60 boys in the class. Rani is 58th from the left, and we know that there are 20 boys to her right. This implies that, to the left of Rani, there are 57 students (including Rani), and out of these, 20 must be boys as she has 20 boys to her right. Therefore, we can calculate the number of girls to her left as:
Total students to the left of Rani - boys to the left of Rani = girls to the left of Rani
57 - (30 - 20) = girls to the left of Rani
57 - 10 = 47 girls to the left of Rani