The ages of three siblings,Leon,Kelley and Jack are in the ratio 3:5:6. The sum of their ages is 42 years.How old is Kelly?

ratio = 3:5:6
Leon = 3
Kelley = 5
Jack = 6

sum ratio = 3+5+6 = 14
sum age = 42

leon = 3/14 x 42 = 9
Kelley = 5/14 x 42 =15
Jack = 6/14 x 42 = 18

so.. kelley age is 15 year

thanks