SOLUTION: Bob and Shelly are shelving cans at the grocery store. Bob puts 17 cans on the shelf per minute, and Shelly puts 23 cans on the shelf per minute. They have to shelve a total of 5

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Bob and Shelly are shelving cans at the grocery store. Bob puts 17 cans on the shelf per minute, and Shelly puts 23 cans on the shelf per minute. They have to shelve a total of 5      Log On


   

Question 1122410: Bob and Shelly are shelving cans at the grocery store. Bob puts 17 cans on the shelf per minute, and Shelly puts 23 cans on the shelf per minute. They have to shelve a total of 500 cans. If Shelly started working 8 minutes before Bob, how long will it take Bob and Shelly to shelve the rest of the cans together?
Found 2 solutions by ikleyn, josmiceli:
Answer by ikleyn(52788) About Me  (Show Source):
You can put this solution on YOUR website!
.
%28500-8%2A23%29%2F%2817%2B23%29 = 7.9 minutes = 7 minutes and 54 seconds.


Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
In 8 min, Shelly stocks +23%2A8+=+184+ cans
There are +500+-+184+=+316+ cans left to stock
—————-
Let +t+ = time for them to finish working
Add their rates of working to get their rate working together
+17+%2B+23+=+316%2Ft+
+40+=+316%2Ft+
+t+=+7.9+ min
It takes them 7.9 min to stock the rest of the cans