Answer:
20percent
Explanation:
First we will find the value of k.
Given
White + Black + Blue + Red = Total
8k+30+(30-2k)+k+5 = 100
8k+30+30-2k+k+5=100
7k+65=100
7k+65-65=100-65
7k=35
k = 35/7 = 5
Now given number of blue cell phone sold is 30-2k = 30 - 2(5) = 30 - 10 = 20,
Percentage of Blue cell phones =
percent