Ambrose and Kaitlin are volunteering at a food bank. They both start at the same time. Kaitlin takes 13 minutes to pack a box with donated food. Ambrose takes 7 minutes to pack a box. After how many minutes will they finish packing boxes at the same time?

They will finish packing boxes at the same time after 91 minutes.

Step-by-step explanation:

From the question,

Kaitlin takes 13 minutes to pack a box while Ambrose takes 7 minutes to pack a box. That is,

Kaitlin will finish packing a box after every 13 minutes and Ambrose will finish packing a box after every 7 minutes.

To determine when they will finish packing boxes at the same time, we will list the times they will finish packing boxes

For Kaitlin, she will finish packing box(es) at the following times:

13th minute, 26th minute, 39th minute, 52nd minute, 65th minute, 78th minute, 91st minute, 104th minute etc.

For Ambrose, he will finish packing box(es) at the following times:

7th minute, 14th minute, 21st minute, 28th minute, 35th minute, 42nd minute, 49th minute, 56th minute, 63rd minute, 70th minute, 77th minute, 84th minute, 91st minute, 98th minute, 105th minute etc.

From above, we can observe that, Ambrose and Kaitlin will finish packing boxes at the 91st minute.

Hence, They will finish packing boxes at the same time after 91 minutes.

x is the total time in minutes for the free response

you are given number of questions as 15 - m and time per item as 8 minutes

to find x multiply the two givens together:

x = 8 * (15-m) = 8(15-m)