Question

The ratio of boys to girls in a class is $3:4.$ If there are $15$ boys in the class, how many students are there altogether?

• A. $30$
• B. $35$
• C. $15$
• D. $20$

Answer 1

The correct option is B $35$

Ratio of boys to girls $=3:4$
Number of boys in the class $=15$
Let’s use a ratio table to find the answer.

Boys	$3$
Girls	$4$

Since the ratio is $3:4,$ the first row will have consecutive multiples of $3$ and the second row will have consecutive multiples of $4.$

Boys	$3$	$6$	$9$	$12$	$15$
Girls	$4$	$8$	$12$	$16$	$20$

We can observe that if the number of boys is 15, there will be 20 girls in the class.

Total number of students = number of boys $+$ number of girls $=15+20=35$