The answer to the question
W = L - 7
WL = 78
(L-7)L = 78
L^2 - 7L - 78 = 0
Factorize: (L-13)(L+6) = 0
L = 13 or -6
A length cannot be negative, so the length must be 13 miles.
The width is 13-7 = 6 miles.
First, you take 36 counters and spread them out. You then separate them into groups of 8 and any left that cannot be separated into groups of 8 are the remainders. When you do this, you will find that you are able to separate 36 into 4 groups of eight, and you will get a remainder of 4, so your answer is 4 remainder 4
