Length and width of the field at in ratio 5:3, if the width is 42 m then what will be length :

A) 100 m

B) 80 m

C) 50 m

D) 70 m 

let the length be 5x and width be 3x respectively
as given in question width is 42 metres but
width is 3x
so , 3x=42
x= 42/3 = 14
if x is 14 then length = 5x = 5×14 =70metres