Question 1160735

A group of friends go out for supper one evening. They decide to share the bill which comes to R960. However, two of them forget their wallets and cannot pay. The remaining friends each now have to pay an extra R40 to cover the cost. How many friends are in the group?
<pre>Let number of friends be N
Then each friend's share should have been: {{{960/N}}} 
With 2 friends not being able to pay, then number who were able to pay was: N - 2, and those who could pay then needed to pay: {{{960/(N - 2)}}}
We then get: {{{matrix(1,3, 960/N, "=", 960/(N - 2) - 40)}}}
{{{matrix(1,3, 24/N, "=", 24/(N - 2) - 1)}}} ----- Reducing fractions by factoring out GCF, 40, in numerator
24(N - 2) = 24N - N(N - 2) ------ Multiplying by LCD, N(N - 2)
{{{matrix(1,3, 24N - 48, "=", 24N - N^2 + 2N)}}}
{{{matrix(1,3, N^2 - 24N - 2N + 24N - 48, "=", 0)}}}
{{{matrix(1,3, N^2 - 2N - 48, "=", 0)}}}
(N - 8)(N + 6) = 0
Number of friends, or {{{highlight_green(matrix(1,3, N, "=", 8))}}}       OR       N = - 6 (ignore)