Problem: a rectangular tiled patio is composed of 90 square tiles . the rectangular patio will be rearranged so that there will be 2 fewer columns of tiles and 4 more rows of tiles . after the change in layout , the patio will still have 90 tiles , and it will still be rectangular . how many rows are in the tile patio before the change in layout ?
Rationale: "r * c = 90 and ( 11 + 4 ) ( c - 2 ) = 90 - - > r = 11 and c = 8 . answer : d ."
annotated_formula: divide(90, divide(add(negate(4), sqrt(add(power(4, 2), multiply(4, multiply(90, 2))))), 2))