Machine a can sort 840 pieces of mail per hour, and machine b can sort 760 pieces per hour. how long will it take both machines running at the same time to sort 12,800 pieces of mail?
a) 4 hours
b) 6 hours
c) 7 hours
d) 8 hours

D) 8 hours

Step-by-step explanation:

Machine A: 840 an hour

Machine B: 760 an hour

h = hour

840 + 760 = 1600

In an hour, they can both sort 1600 mails.

1600h = 12800

Divide each side by 1600

h = 8

840 * 8 = 6720

760 * 8 = 6080

6720 + 6080 = 12,800

answer: d. $20

step-by-step explanation:

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