Verified answer

Answer:

10 white marbles

Step-by-step explanation:

yellow marble = x

white marble = y

total of marble = x + y = 35

probability of picking a yellow marble = x/35 = 5/7

from,

x/35 = 5/7

x/35 = 25/35

x = 25

from,

x + y = 35

25 + y = 35

y = 10

therefore, there are 10 white marbles