An explicit equation is an equation used to find a term in a sequence without using the any previous terms. For example, if I have the set of numbers 1, 3, 5, 7, 9, my explicit equation is F(n)=2(n-1)+1. If I plug 1 in for n, I get F(1)= 2(0)+1, which is 1, my first term.
Hope this made sense.
300miles/20sec=?miles/1min
900miles/60sec=?miles/1min
900miles/1min=?miles/min
?=900 miles
7 days because 12 per day 12×6=72 but you need 3 more acres so it would be another day for it to be 7