Question 1185291
Alex, Benjamin and Caris shared some pancakes. Caris took {{{3/4}}} of the
pancakes and {{{1/4}}} of a pancake. Benjamin took {{{3/4}}} of the remaining number of
pancakes and {{{1/4}}} of a pancake. There were only 6 pancakes left for Alex.
How many pancakes were there at first? 
<pre>Let original number of pancakes be P
After Caris took {{{3/4}}} of original number of pancakes, plus {{{(1/4)^(th)}}} of a pancake, {{{matrix(1,5, (1/4)P - 1/4, "=", P/4 - 1/4, "=", (P - 1)/4)}}} pancakes were left
After Benjamin took {{{3/4}}} of the remaining number of pancakes, plus {{{(1/4)^(th)}}} of a pancake, {{{matrix(1,7, (1/4) * ((P - 1)/4) - 1/4, "=", (P - 1)/16 - 1/4, "=", (P - 1)/16 - 4/16, "=", (P - 5)/16)}}} were left
With 6 pancakes remaining in the end, we get: {{{matrix(1,3, (P - 5)/16, "=", 6)}}}
P - 5 = 96 ------ Cross-multiplying

Original number of pancakes, or {{{highlight_green(matrix(1,5, P, "=", 96 + 5, "=", highlight(101)))}}}

You can do the CHECK!!</pre>