Question

How long is a rectangular field with a width of 3/5 mile and an area of 21/50 square mile?

Answer 1

A = B*L

A = 21/50 sq miles
B = 3/5 mile
L = ? mile

L = A/B
L = (21/50)/(3/5)

* dividing by fraction is same as multiplying by it's reciprocal

L = (21/50)*(5/3)
L = (21*5)/(50*3)
L = 105/150

*divide both numerator & denominator by 5

L = 21/30

*divide both numerator & denominator by 3

L = 7/10 miles

Answer 2

`w=(3)/(5)mi\\\\l=?\\\\A_{\fbox{ }}=w* l;\ A_{\fbox{ }}=(21)/(50)mi^2\\\\(3)/(5)l=(21)/(50)\ \ \ \ \ |multiply\ both\ sides\ by\ (5)/(3)\\\\l=(21)/(50)*(5)/(3)\\\\l=(7)/(10)\\\\Answer:\boxed{(7)/(10)mi=0.7mi}`