Answer:
Pieces remaining = 1 - (1/4 + 1/4) - (1/2 x1/5) = 1/2 - (1/2 x1/5) = 1/2 - 1/10 = 4/10
Therefore, 4/10 x 20 = 8 pieces.
Explanation:
Sophie ate 1/4 = 5 pieces
Glenn ate 1/4 = 5 pieces
Remaining pieces = 20 - 5 - 5 = 10 pieces
On Monday, Sophie ate = 1/5 x 10 = 2 pieces
Therefore, remaining pieces = 10 - 2 pieces = 8 pieces
Sophie and Glenn consumed half of the pie the first day. This is equal to 10 pieces. The remaining pieces will be 10. If, on Monday, Sophie ate 1/5 of 10 pieces, representing 2 pieces, the number left over is 10 Minus 2, which equals 8 pieces.