PSLE
Reggie packed 402 scones into large and small boxes. He filled each large box with 10 scones and each small box with 6 scones. All the boxes were full and no scones were left over. What was the least number of boxes used by Reggie?
To have the least number of boxes, Reggie had to use as many as large boxes as possible.

If Reggie used only large boxes,
number of large boxes used
= 402 ÷ 10
= 40 r 2 (x) There should be no remaining scones left.

If 40 large boxes are used, there are 2 scones left, Reggie had to use less large boxes so that the rest of the scones were packed in small boxes.

If Reggie used 39 large boxes,
number of scones to be packed in small boxes
= 402 - (39 x 10)
= 402 - 390
= 12

Number of small boxes needed to pack 12 scones
= 12 ÷ 6
= 2 (✓) There is no remaining scones left.

Least number of boxes that Reggie used
= 39 + 2
= 41

Answer(s): 41