Answer:
12
Step-by-step explanation:
The 5 parts of the ratio represents 10 boys.
Divide number of boys by 5 to find the value of one part of the ratio.
= 2 ← value of 1 part of the ratio
There are 6 parts of the ratio representing girls, thus
6 × 2 = 12 ← number of girls in the class
5 : 6 = Number of boys to girls
(We have to ×2 to get from 5 to 10 so we must ×2 from 6 to 12)
10 : ? = Number of Boys to girls
10 : 12 = Number of Boys to girls
Answer: the answer is 1.499495
2.65 + 3.78 = 6.43
B, D are equal to 6.43