Answer:
12
Step-by-step explanation:
sum the parts of the ratio, 2 + 4 = 6 parts
Divide total number of socks by 6 to find the value of one part of the ratio.
18 ÷ 6 = 3 ← value of 1 part of the ratio, thus
4 parts = 4 × 3 = 12 ← number of white socks
