Donut Haven fries donuts in batches of $20$, but sells them in boxes of $13$. If Donut Haven fries just enough batches of $20$ to pack $44$ full boxes of $13$ donuts, how many donuts will be left over?

The number of doughnuts left over are 8 doughnuts

Step-by-step explanation:

The information given are;

The number of doughnuts fried per batch = 20 doughnuts

The number of doughnuts contained in a pack = 13 doughnuts

The number of doughnut batches just fried = 20 batches

The number of packs filled = 44 packs

The number of packs filled with the fried = 44 packs

The number of doughnuts per pack = 13 doughnuts

The number of doughnuts in the pack = The number of packs filled with the fried × The number of doughnuts per pack

The number of doughnuts in the pack = 44 × 13 = 572 doughnuts

Given that the number of batches of doughnuts fried = X batches and the amount of left over = Y doughnuts, where each batch contains 20 doughnuts, we have;

Number of doughnuts fried = Number of batches of doughnuts fried × Number of doughnuts per batch

Number of doughnuts fried = X × 20 =20×X doughnuts

Therefore we have;

Number of doughnuts fried = The number of doughnuts in the pack + The number of doughnuts left over

Which gives;

20×X = 572 + Y where Y < 20

Checking we have multiples of 20 are 560, 580

Given that 520 is the next multiple of 20 after 572, we have;

The number of doughnuts fried = 580 and the number of left over = 580 -  572 = 8 doughnuts.