Question 267971
Of the students who chose blue,let x=fraction of boys who chose blue

(1/2)(4/10)=(1/2)(2/5)=1/5 of the boys chose blue
(1/5)(6/10)=(1/5)(3/5)=3/25 of the girls chose blue
And we know that 1/5 + 3/25=5/25 + 3/25=8/25 of the students chose blue
So, our equation to solve is:
(8/25)x=1/5
x=(1/5)/(8/25) multiply numerator and denominator right side by(25/8)
x=(1/5)(25/8)/(8/25)(25/8)=(5/8)/1=5/8 the fraction of boys that chose blue

Does this help??-----ptaylor