PSLE
Flynn packed 388 muffins into large and small boxes. He filled each large box with 16 muffins and each small box with 4 muffins. All the boxes were full and no muffins were left over. What was the least number of boxes used by Flynn?
To have the least number of boxes, Flynn had to use as many as large boxes as possible.

If Flynn used only large boxes,
number of large boxes used
= 388 ÷ 16
= 24 r 4 (x) There should be no remaining muffins left.

If 24 large boxes are used, there are 4 muffins left, Flynn had to use less large boxes so that the rest of the muffins were packed in small boxes.

If Flynn used 23 large boxes,
number of muffins to be packed in small boxes
= 388 - (23 x 16)
= 388 - 368
= 20

Number of small boxes needed to pack 20 muffins
= 20 ÷ 4
= 5 (✓) There is no remaining muffins left.

Least number of boxes that Flynn used
= 23 + 5
= 28

Answer(s): 28